rsv research

Since the beginning of flu season in October, respiratory syncytial virus (RSV) has been on the rise all around the country. RSV typically hospitalizes about 60,000 children each year in the U.S, with the infection season peaking in the winter.

However, according to the CDC, doctors have found more cases in each week this past October than any week in the last two years.

This has driven our dedication to RSV research and to training medical students and practitioners for RSV cases and care. All this is possible with our infant lung simulators.

Understanding the Impact of RSV in Children

RSV is a respiratory virus that causes mild, cold-like symptoms in most people, with an average 7 day recovery time. However, infants are more likely to face far more significant side effects and longer recovery times. 

In children younger than 12 months, RSV is the most common cause of bronchiolitis and pneumonia. Furthermore, one to two out of every 100 children younger than 6 months of age with RSV infection may need to be hospitalized.

Scientists are developing several vaccines, monoclonal antibodies, and antiviral therapies to help protect infants and young children, pregnant people (to protect their unborn babies), and older adults from severe infection.

However, many hospitals, facing staffing shortages, remain overwhelmed this RSV season. Medical schools and hospital leaders should prepare practitioners to treat RSV cases now more than ever. 

Simulating RSV On Our Infant Lung Simulator

Unlike other similar models on the market today, our Infant Lung Simulator provides vast flexibility and several applications for simulating a wide range of patient populations. 

This device realistically simulates infant lung capacity, clinically trains others on ventilator use and respiratory care in a hands-on manner, and simulates unexpected or complex scenarios. 

Additionally, biomedical engineers, manufacturers, and service companies can use these simulators to test the performance of mechanical ventilators and similar respiratory care devices; all in an effort to ensure that their functions are adequate for illnesses like RSV.

How Do Our Simulators Help RSV Patients?

Professionals use our lung simulators to develop new therapy strategies while working against a realistic “load” (simulated lung mechanics). Further, our devices allow trainers to simulate a wide variety of healthy and diseased lung conditions to provide training for proper care of those with viruses or other conditions. Simply put; our devices are extremely versatile.

We take pride in our ability to train and educate current and future medical professionals, with a goal of contributing to research and new developments for care of those with respiratory illness. 

Proactively Train Your Hospital Staff for a Better 2023

We know that good RSV-trained providers are invaluable — and not exactly interchangeable. With RSV still on the rise (and predicted to occur every year), proactive RSV research, training and development is more important than ever. 

To learn more about our Infant Lung Simulator, visit our Lung Simulator Page or contact us directly today!

michigan lung simulator

For over 45 years, our Michigan Lung Simulator has offered residual lung volumes and a dynamic response to therapy that realistically represents all the functions of the human pulmonary system. Our devices are more advanced now than ever, thanks to our ever-changing technology and dedication to research.

We receive many questions about our lung simulators and their operations. Below are the questions we see most often

1. What Is The Difference Between A “Test Lung” And A “Michigan Lung Simulator”?

We’ve used the terms “test lung,” “training test lung,” and “Michigan lung simulator” to describe our TTL® and PneuView® products. In some ways, these terms are interchangeable. However, in a broader sense, the term “test lung” may include devices that are very simplistic rubber or latex bags. 

On the other hand, “lung simulators” describe a more complex system that accurately mimics the dynamic mechanical characteristics of the human pulmonary system.

2. What Is The Fundamental Purpose Of A Michigan Lung Simulator?

There are several situations and settings where the use of a lung simulator is crucial. A solid lung simulator represents the functions of the human pulmonary system, as well as a range of healthy and diseased lung conditions. 

A lung simulator should allow you to create, monitor and control those forces.  For the following applications and more, a high-quality lung simulator is needed:

  • Designing mechanical ventilators and other respiratory apparatus
  • Developing new modes of ventilation support
  • Training respiratory care and other medical professionals
  • Performing periodic testing and maintenance on ventilation and support devices
  • Troubleshooting equipment problems using a realistic “load”

3. How Do The TTL® And PneuView® Systems Model The Dynamic Compliance And Resistance Characteristic Of The Human Lungs?

Our TTL® and PneuView® systems use a bellows and spring to simulate the compliance characteristics of the lung. The spring can be positioned at several different points along the Top Plate of the simulator to create a lung compliance that ranges from very compliant to normal to very non-compliant (or stiff). 

The resistance characteristics of the lung are set using fixed-orifice parabolic resistors that may be positioned to add resistance to the upper and/or lower airway assembly.  A range of resistors allow for simulation of both healthy and diseased lung conditions.

4. What Is Factory Calibration?

Factory calibration involves tuning all aspects of sensor, electronic, mechanical and software to ensure maximum accuracy of the measurements and simulated parameters provided by TTL® & PneuView® systems. 

Calibration procedures include the setting of the compliance and resistance characteristics of the lungs, as well as setting offset and gain characteristics for each of the pressure transducer channels.

5. How Do I Read The Tidal Volume On The Lung Simulators?

Each simulated lung in the TTL® or PneuView® System has a physical volume scale behind the Top Plate. There is also a plastic pointer and label on the Top Plate that can be used to indicate lung volume. 

To ensure the most accurate indication of lung volume, the pointer on the top plate must correspond to the compliance setting on the lung. When set appropriately, the arrow will point to the gas volume in the lung. 

Note: When using PEEP or CPAP, the starting volume (baseline volume) is greater than zero. The tidal volume would be the total indicated volume minus the baseline volume.

The volume indicator lines on the label are curved, more so as the compliance setting decreases. This is due to the sideways distention of the bellows that occurs during filling of the lung under pressure.

6. Are Michigan Lung Simulators Suitable For Tests With Aerosols Or Just Dry Air Only?

Water vapor will not damage the simulator.  However, we generally don’t recommend introducing aerosolized substances into the lung chambers of our TTL® and PneuView® simulators for the following reasons:

  • Substances other than water can be corrosive to the polyurethane bellows, and/or may accumulate on the ribs of the bellows causing them to stick, become brittle, or not function properly.
  • There is no simple way to “drain” the bellows of any accumulated fluid. If using sterile/demineralized water, you may blow dry gas through the unit until it is fully dried.

Many of our customers have used the TTL® or PneuView® specifically to evaluate aerosol delivery with various devices and/or breathing patterns. In such cases, the aerosolized substance is typically collected using a hydrostatic filter placed in the simulated airway, prior to entering the lung bellows.

Let Us Answer Your Questions

If you have any other questions about our lung simulators, visit our FAQ page or contact us directly!

sbl michigan instruments

After multiple requests from our customers, Michigan Instruments added it’s newest product–the Spontaneous Breathing Lung.  Our Spontaneous Breathing Lung Simulator (SBL™) offers a new and improved way to create spontaneous breathing. The SBL™ is useful for designing, testing, and training on non-invasive and supportive modes of ventilation and oxygenation.

Since its release, we’ve received many inquiries from medical professionals, researchers, and educators about this device. Keep reading to learn the most common questions surrounding the SBL™, and our answers to them.

1. Which Models of TTL and PneuView Can Be Driven By The SBL™ Spontaneous Breathing Lung Module?

The SBL™ Module is designed to operate on any Michigan Instruments lung simulator. Therefore, it can be used on the Single Adult, Dual Adult, and Adult-Infant models of TTL and PneuView products.

2. Can I Use The SBL™ In Conjunction With The PneuView Software?

There is nothing that prevents the use of the PneuView software (PV3) in conjunction with the SBL™. However, it’s important to remember that there are limitations to the use of the PV3 software in the SBL™. 

The PV3 software has more difficulty interpreting the negative pressures developed in a spontaneous breathing simulation. Therefore, certain values displayed by the PV3 software will be inaccurate when the PV3 software is used in conjunction with the SBL™.

3. Why Does The SBL™ Stutter During Inspiration Or Completely Stop Running Sometimes?

When the SBL™ stutters during use, or even if it stops operating, it’s usually due to protections programmed into the software to limit excess negative intra-lung pressure. Therefore, if the lifting load is too high or the negative pressure seen during inspiration is excessive, the motor operation will stutter or cease altogether and a message will be displayed for the user. 

This happens intentionally in order to prevent damage to the device. In these cases, settings should be adjusted to a safe operating range (i.e., reduce airway resistance, increase compliance, increase inspiratory time and/or reduce tidal volume).

4. Sometimes, I’m Not Able To Get The Rate And Volume Combination That I Set In The SBL™ Software. Is That A Problem?

Simply put, there are just certain combinations of breathing patterns and lung mechanics that are beyond the limits of the SBL™—specifically, the set lung compliance limits the available tidal volume options in the software.

5. Can I Retrofit the SBL™ To My Michigan Instruments TTL In The Field?

The retrofit process requires several modifications to the TTL or PneuView device. Furthermore, adding the SBL™ to an existing Lung Simulator must be done at the Michigan Instruments factory.

6. Can The SBL™ Module Be Added To Any TTL Or PneuView System That I Own?

No. The SBL™ is designed to be installed on one of the newer Michigan Instruments Lung Simulator models (TTL or PneuView – version 3.x). The SBL™ Module will not fit onto older models of TTL and PneuView. 

However, the SBL can be incorporated into your new Michigan Instruments Lung Simulator, or it can be retrofitted to Gen3 units.

We Can Answer All Your Questions

If you have any other questions about the Michigan Instruments’ SBL or any other devices, visit our FAQ page or contact us directly!

respiratory therapy after covid

Like many other healthcare professionals, respiratory therapists (RTs) have had their work cut out for them ever since the outbreak of COVID-19 in early 2020. Their role in the medical field, which was always considered demanding, is now even more complex and ever-changing. 

However, these challenges have pushed them to work even harder to research and practice the best care for those with respiratory complications due to COVID-19. 

Respiratory Therapists’ Role During the COVID-19 Pandemic

After over 2 years of extensive research, it has been proven that COVID-19 can have a major impact on the respiratory system. More severe cases of COVID-19 and its variants can cause long lasting complications to a person’s respiratory system.

Adults aged 65+ and those with other underlying health conditions such as heart disease, cancer, and chronic obstructive pulmonary disease (COPD), may have serious symptoms; with some even having long-term effects.

As the number of patients with COVID-19 has grown, so has the demand for respiratory therapists. Respiratory therapists have provided treatment for those with COVID-19-related respiratory complications in many ways. 

One way is through pulmonary rehabilitation, which helps patients improve lung function, reduce symptoms and improve quality of life. Respiratory therapists help aid these programs through education, exercise, and support. 

How Our Spontaneous Breathing Lung Aids in Respiratory Education

We understand that COVID-19 has affected the respiratory systems of many patients throughout the last few years, and will continue to do so as the virus persists. This is why we are proud to have our Lung Simulators used to contribute to respiratory studies.. 

We recently added the Spontaneous Breathing Lung (SBL™) to our product line. The SBL™ offers a new and improved way to create spontaneous breathing. It’s available as an independent device, or as an upgrade to the current generation TTL or PneuView Simulator.

These simulations are useful for designing, testing, and providing training on non-invasive and supportive modes of ventilation and oxygenation. Additionally, it allows control of breath rate, tidal volume, inspiratory time, and inspiratory flow pattern. 

All these features and more make this device the ideal tool for teaching and learning about COVID-19’s respiratory impact.

Going to AARC Congress 2022? We’ll See You There!

To show our dedication, we will be attending AARC Congress this November. We’re so excited to showcase the SBL™, while connecting with respiratory therapy professionals from across the country!

Learn more about our high-quality lung simulators that you can touch, see, and modify and the differences between each one. Questions? Request a quote, or ask us anything!

lung health day

According to WebMD, tens of millions have lung disease in the U.S. alone, caused by smoking, infections, or genetic predisposition. On October 26th, we celebrate Lung Health Day in the United States, which is dedicated to raising awareness about chronic lung complications and educating others on how we can make a difference. 

Michigan Instruments is dedicated to furthering lung research and health here in the United States—and worldwide. 

What are the Most Common Lung Complications?

The most common lung complications in the U.S. include asthma, chronic obstructive pulmonary disease (COPD), and pneumonia. 

  • Asthma affects approximately 25 million people in the U.S., and is a disease that causes episodes of wheezing, breathlessness, tightness in the chest, and coughing. Asthma complications can be avoided by determining trigger attacks or taking medicine. 
  • COPD refers to a group of diseases which leads to blockage of airflow and trouble breathing. It includes emphysema and chronic bronchitis. Sixteen million Americans have this disease, which has no cure. However, there are treatments which include oral steroids, antibiotics, and smoking cessation programs.
  • Pneumonia is an infection of the lungs that affects about one million people in the U.S. every year. Common causes include viruses, bacteria, smoking, or underlying conditions such as diabetes. This infection can be prevented with vaccines or antivirals. 

At Michigan Instruments, our lung simulators are available in Adult and Infant models and can replicate hundreds of healthy and diseased lung conditions. This is all, of course, while providing accurate measurements and data that inform your testing, research, and training.

Lung Health Resources

It’s important to understand the lung complications that affect so many Americans every day. Here are some resources you can use to learn more:

Click here to learn how our lung simulators can provide innovative research and testing on the future of lung health in the U.S. and worldwide.

How Michigan Instruments is Making an Impact 

Michigan Instruments is committed to furthering the advancement of lung health in the U.S.—and worldwide. We do this by providing state of the art devices for research. 

Additionally, we’re passionate about contributing to education. In the past, we’ve worked with many universities on grants and funding options.

We take pride in teaching students the basic concepts of lung compliance and airway resistance. Our devices provide simulation of a variety of lung conditions and offer a dynamic response to therapy that realistically represents the human pulmonary system.

Learn more about our Adult, Infant, and Spontaneous Breathing Lung (SBL™) Lung Simulator devices, or contact one of our representatives to learn more!

spontaneous breathing lung simulator

Michigan Instruments is excited to introduce the Spontaneous Breathing Lung (SBL™)! The new and improved way to create spontaneous breathing with accurate stimulation of a breathing patient. 

Spontaneous breathing simulations are useful for testing, designing, and training on non-invasive and supportive modes of ventilation, as well as oxygenation.

The SBL is available as an independent device or an add-on to any current generation TTL or PneuView simulator from Michigan Instruments. 

Interested in seeing the SBL in person? Join us at the Fall AARC Show 2022 on November 9-11 in New Orleans, LA. Booth 1514.

In the meantime, keep reading to learn more about the SBL! 

Features of the SBL

The SBL offers a variety of controls to provide accurate simulation of a breathing patient, including breath rate, tidal volume, and more. 

The controls and ranges of measurements offered on the SBL are listed below: 

  • Breath Rate 2 to 30 per minute
  • Tidal Volume  100 to 1,800 ml
  • Inspiratory times .5 to 5.0 seconds
  • Inspiratory Flow Pattern Square or Sine
  • Inspiratory Flow Waveforms

Training and Testing

The industry for therapeutic devices and modalities that are made to function with a spontaneous breathing patient is growing. That’s why it’s important for Michigan Instruments to offer the SBL as a solution to simulate the wide variety of scenarios and breathing patterns.

This is the perfect device to use during education and training of students or established professionals. The SBL also facilitates troubleshooting and testing of devices meant to operate on spontaneous breathing patients.

Use the SBL to test your device’s ability to detect the start of a breath, to avoid breath-stacking, and more. 

Research and Development 

The SBL breathing is controlled by using our simple and intuitive, windows-based software program, and can be your tool for all kinds of research in various fields. 

From studying the dispersion of aerosols and inhalers to assessing the responsiveness of new technologies, Michigan Instruments devices have been historically used for all types of research. 

Any research requiring breathing is a candidate for the SBL, contact us to discuss your project.

Breathe Easier with the SBL

The new Spontaneous Breathing Lung from Michigan Instruments—Spontaneous Breathing Simulation made:

  • Easy
  • Accurate
  • Reliable.

For more information about the SBL, find it here. For more information about the Fall AARC Show 2022, click here.

We’re excited to see you at the show! In the meantime, contact us to answer any questions or to request a quote!​​

Lung Simulators: Why Choose Michigan Instruments?

Lung simulators are designed to replicate the function of healthy and diseased human lungs for testing, teaching and training. Comparing the features, settings and the realistic nature of a lung simulator is vital to its success and effectiveness.

Below, we outline the 3 main features of our lung simulators.

1. Realistic Appearance and Feel

When utilizing lung simulators in teaching, training and testing, it’s important to create the most realistic scenario as possible.  

Michigan Instruments’ simulators do that as they are built fully to scale, and offer realistic residual lung volumes and capacities. Our devices move, breathe and feel like real lungs when ventilated. 

Additionally, our Training Test Lungs (TTL) and Pneuview Systems are available in adult and infant models. 

2. Enhanced Lung Simulator Settings 

When using our devices, it’s best to have a varied range of settings for compliance and resistance. Our TLL and Pneuview systems provide enhanced settings that exceed the capabilities of many other simulators on today’s market.

Our devices include a variety of settings and capabilities, such as:

  • different lung conditions and pathologies,
  • tools for teaching and training, and 
  • measurements for lung volume, lung and airway pressure, and more.

3. Affordable Cost

Michigan Instruments’ lung simulators and PneuView systems offer your institution a realistic simulation, with an array of features and settings—at a fraction of the cost of other devices available.

Which One is Best For You?

While both the TTL and Pneuview Systems offer a variety of dynamic features and simulations, it all comes down to which one is best for your organization’s training, testing and research needs.

Learn more about our high-quality lung simulators that you can touch, see, and modify and the differences between each one. Questions? Request a quote, or ask us anything!

test lung for ventilator

When lives are hanging in the balance, it’s imperative to know how to use a test lung for ventilator testing and calibration. Our lung simulators help to do that.

Because of its significance, we’ve outlined the testing applications of lung simulators, their benefits of use, and more: 

Why Do I Need To Test and Calibrate Ventilators?

Did you know that testing using Lung Simulators helps troubleshoot problems and verify proper operation of devices before they’re used on patients? 

No matter what, all ventilators must be tested and calibrated before they can be used on a patient. This is to avoid adverse side effects.  

Additionally, you must re-test and re-calibrate ventilators periodically to ensure they’re performing to established standards and manufacturer specifications. 

Testing ventilators also helps medical staff understand what to expect from the ventilators and how each mode, in particular, will perform under real-world conditions.

The Uses and Testing Applications of Our Lung Simulator

There are many uses and testing applications of the Michigan Instruments’ Lung Simulator, such as the:

  • Design, test and improve Respiratory Care products
  • Confirm the performance of products prior to delivery to customers
  • Troubleshoot performance problems, applying realistic “loads” on the products
  • Periodic verification of ventilator performance
  • Train your Engineering, Tech Support, Marketing, and Sales personnel on use of your products
  • Demonstrate products to customers and prospects

Lung Simulators Offer Vast Benefits

There are many benefits to our lung simulators. First, they provide real-time feedback, with built-in volume scales and pressure gauges on all units. Multiple ports provide access for additional monitoring, sampling, or introduction of gas or other agents during testing. 

Additionally, our simulators with the PneuView software allow you to view, record, and replay the data from the simulators. 

Our lung simulators are available in adult and infant versions, in single and dual-lung models. Their design helps simulate a wide range of patients and lung conditions. Medical manufacturers and others count on the accuracy, versatility and durability of these devices day in and day out.

Interested in learning more about adding one of our Lung Simulators to your hospital, laboratory or quality control department? Contact us to receive a quote and more information today!

The 5+ Benefits of Simulation Over Traditional Learning

Saving lives is the most important thing in healthcare and emergency medical services. This is why huge advancements have been made in medical education, including simulation over traditional classroom learning. 

“In medicine, simulation offers good scope for training of interdisciplinary medical teams. The realistic scenarios and equipment allows for retraining and practice till one can master the procedure or skill… Teamwork training conducted in the simulated environment may offer an additive benefit to the traditional didactic instruction, enhance performance, and possibly also help reduce errors.” [1]

Below, we outline the top 6 benefits of simulation, and how it compares to traditional learning.

1. Bridges the Gap Between Training and Reality

Simulation improves both patient care and outcomes by providing more real-life scenarios for aspiring Respiratory Therapists and EMS Professionals. 

Practicing techniques and clinical skills, such as administering oxygen, is made easier with a simulation device that moves and “breathes” like a real human lung or lungs when ventilated. 

2. Simulation Ensures Patient Safety

Rather than practicing on live patients, simulation-based education ensures patient safety by allowing mistakes and the ability to correct them. 

Many lung simulators are simple at best, which isn’t ideal for real-life patient safety. By using a solid simulator that can mimic the realistic mechanics of the human pulmonary system (such as our Lung Simulators), medical students and professionals alike can perfect their skills without the burden of life vs. death hanging over their shoulders.

Interested in learning more about our Lung Simulators? Contact us to receive a quote and more information today!

3. Safely Prepares for a Variety of Patient Scenarios

A simulation device should offer a range of calibrated lung compliance and airway resistance settings giving students and professionals an immersive, nearly hands-on experience. This allows the replication of hundreds of both healthy and diseased lung conditions, while providing accurate data to inform your testing, research and training. 

Our Lung Simulators are available in three models: Single Adult, Dual Adult and Adult-Infant. With three models for students and professionals to choose from, this allows for the ability to simulate a wider variety of patient sizes and health situations, thus improving techniques that will be used in real-life patient scenarios.

4. Reduced Errors in Training = Improved Patient Care

“To Err Is Human”, a report released by the Institute of Medicine (IOM) in 1999, revealed that medical errors result in a minimum of 44,000 and perhaps as many as 98,000 deaths per year in the United States. 

This landmark report called for improved training among medical students through a variety of ways, including simulation-based education. While the COVID-19 pandemic has forced universities and training centers to largely discontinue traditional classroom learning, simulation-based education has risen with its remote, digital education component.

Interested in learning more about our Lung Simulators? Contact us to receive a quote and more information today!

5. Teaches Both Students and Professionals Communication Skills

The healthcare industry is moving towards a multidisciplinary team to deliver prime patient care. Therefore, possessing excellent communication skills is just as important as clinical skills for both Respiratory Therapists, EMS Professionals, and Surgeons alike. 

In particular, Respiratory Therapists are moving toward a patient-centered approach that can improve the management of diseases, such as Asthma, while also focusing on disease prevention and health promotion for patients.

6. Allows the Reassessment of Any Scenario to Identify Ways to Improve 

As mentioned above, simulation-based education allows for students to make mistakes (and correct them) without compromising a real-life patient’s health. 

Designed with our users’ needs in mind, our PneuView Software accurately provides numeric and graphical data from our Lung Simulator devices in real time. Additionally, you can save and export data for later review and analysis. This is especially useful for documentation of testing, or when access to certain ventilation technology is not always available. 

Interested in learning more about adding one of our Lung Simulators to your classroom, training program or research facility? Contact us to receive a quote and more information today!

(1) Lateef F. Simulation-based learning: Just like the real thing. J Emerg Trauma Shock. 2010;3(4):348–52.

Why Lung Simulators are Ideal for Training, Testing, Research & Development

Michigan Instruments Lung Simulators for adults and infants offer the most realistic and accurate simulations of the human pulmonary system available on the market. Because of this, our Lung Simulators are an ideal tool for medical professionals, manufacturers, and educators to provide hands-on training, test respiratory care products and devices and help to advance the research and development of new ideas and technologies.


Michigan Instruments’ Lung Simulators have been used in a majority of the respiratory therapy training programs in the United States, and even throughout the world. They work well in a classroom setting because they help to make the connection between theory and clinical experience in a safe setting by: 

  • Providing hands-on experience and real-time feedback to effectively simulate a response to the apparatus or technique being used
  • Simulating a wide variety of healthy and diseased lung conditions by altering the lung compliance and airway resistance in a one- or two-lung simulation
  • Allowing students to work with a realistic total lung volume and residual volume (especially when using the Dual Adult Test Lung Simulators)
  • When used with our PneuView Software, it lets educators store recordings of ventilation runs for later demonstration and evaluations, and students can conduct research and easily save their data

Testing Ventilators & Respiratory Care Products

Using Lung Simulators in performance testing of mechanical ventilators and other respiratory care devices can be an integral part of risk management and quality control within the medical setting. Testing using Lung Simulators can help troubleshoot problems and verify proper operation of devices before they’re used on patients.

Medical Research & Development

Lung Simulators have been used in a variety of research and development settings to assess concepts, designs, prototypes and final products. By applying realistic respiratory mechanics and dynamics to a concept or device, our Lung Simulators can evaluate new ideas and technologies while providing real-time feedback and data collection for documentation, later review, and analysis. 

For example, during the past year, Michigan Instruments’ Lung Simulators have aided the research and development of ventilator solutions with organizations like NASA, Ford Motor Company, Cornell University, etc. to combat the shortages caused by the COVID-19 pandemic.

Our lung simulators have even been customized to mimic the respiratory system of a dolphin to test veterinary medical procedures, before operating on the live animal.

Ready to learn why thousands of educators, researchers, manufacturers, and quality assurance professionals worldwide have chosen Michigan Instruments Lung Simulators? Contact our representatives to learn more and request a quote