+1.818.357.5647Live US Agents 8AM - 9PM EST

90 Day Guarantee | Engraving Available | Free Parts for Life and Lifetime Warranty


How do I return a purchase?

We like to keep things simple. We give you 90 days to try our products, and if you don't love your MDF Instruments product, simply initiate a return by contacting our customer service department at customer.service@mdfinstruments.com. Upon receipt of the returned product, we will issue a refund for the purchase price of the item(s), not including the original shipping charges. Please give us a few days to process your return.

Stethoscopes that have been engraved are not covered under the 90 Day Return policy. If you have received a stethoscope with an engraving error, please let us know and we will replace it. If your item arrives damaged or contains a manufacturer's defect, it is covered under our Lifetime Warranty. If for any reason you would like to exchange a product outside of our 90 Day Return policy please contact us.

All returns must have an RMA number (Return Merchandise Authorization), so please contact us to receive this number. If an RMA number is not obtained prior to the return, a $5 handling fee will be applied. To request an RMA, please email customer.service@mdfinstruments.com and include the following information: original purchase number, name and the reason for the RMA request. Returns must be shipped within five business days after the RMA is issued. All returns must be received within 10 business days of the RMA being issued. We are unable to refund any import duties/tariffs, original or return shipping costs.

Bulk returns may be subject to a 15% restocking fee.

Can I return something that was given to me as a gift?

If you are able to provide us with the original order number, we will process the refund under our 90 Day Return policy guidelines. If you do not have the original order number, we will not be able to offer a refund but we would be happy to offer an exchange and help find the perfect stethoscope for you.

How do I exchange my order for something else?

We want you to love your stethoscope, so if you would like to make an exchange, please contact us with the order number at customer.service@mdfinstruments.com. If there is a price difference, we will refund the difference on the original order or charge the difference if you would like to upgrade your MDF Instrument.

Do I have to pay for the shipping to return my order?

We kindly request that you pay for the shipping cost to return your order. If you have received an incorrect or defective product, we would be happy to cover the shipping cost for you. For any issues with shipping your item for return, please contact us.

How long will it take to receive a refund?

Please allow us a few business days to process your return and initiate the refund. We will contact you with any questions on your return but once the refund is processed, it will take 2-3 business to post in your account, depending on your bank.

Payment Information

What forms of payment do you accept?

We accept Visa, MasterCard, Discover, American Express, PayPal and Apple Pay.

Do you charge sales tax on any item?

We charge sales tax per state regulations.

Shipping Information

How long will shipping take?

The shipping time will depend on the shipment method and delivery location. For US orders we offer Standard, Premium and Express shipping, and provide an estimated delivery time on the product page and at checkout. If you are uncertain if you will receive your product in time, please give us a call at 818.357.5647 and remember to take into consideration an additional three business days for stethoscope orders with engraving.

Can I place an order with expedited shipping?

At checkout you can select the option for Premium (3-8 business days) or Express Shipping (2-3 business days) for a fee. Orders over $49.99 receive free Standard shipping (5-10 business days).

Lifetime Warranty

Does my instrument have a Lifetime Warranty?

Our Stethoscopes (excluding the single-use line), Sphygmomanometers and Reflex Hammers have a Lifetime Warranty.

Is replacement tubing covered under the Lifetime Warranty?

The Lifetime Warranty covers the entire stethoscope including the tubing, against defects in material and craftsmanship. Your stethoscope will be repaired or replaced without charge for the life of the instrument in case of defect. However, the Lifetime Warranty does not cover discolored tubing (not related to manufacturing defect), theft, loss, disposal, improper handling, accidents or failure to follow operating instructions.

How do I replace the headset and tubing on my stethoscope?

To make a Lifetime Warranty request for a replacement headset and tubing, please register your stethoscope if you haven't already. You can register and make the request at online registration and service form or feel free to contacts us and we will complete this process for you. Once you receive the replacement headset and tubing, you will remove your chestpiece by pulling it firmly from the end of the damaged tubing. Then, reinsert the chestpiece into the end of the new tubing. Click here to watch a video demonstrating this process.

How do I replace the battery in my MDF® Pulse Time Stethoscope?

Your Pulse Time clock requires a LR-41 battery, available at any local drugstore or jewelry/watch store. Click here to watch a video of replacing the clock battery.

Free-Parts-For-Life Program

If the Free-Parts-For-Life Program really free?

Yes, our Free-Parts-For-Life Program is really free.

Free-Parts-For-Life shipments will be sent to the shipping address on the original order or location of purchase. If you have moved to another country other than the original shipping location, please read our guidelines here.

How do I get parts for my stethoscope?

Simply register if you haven't already, and make the request online at online registration and service form or call us at 818.357.5647 and we'll get you taken care of.

What is included in the Free-Parts-For-Life-Program?

The parts include our ComfortSeal® Eartips in three sizes (small, medium and large), ID Tag, diaphragms, retaining rings and non-chill rings.

How long will it take to receive my parts?

Our Free-Parts-For-Life Program shipments to the US and Canada are sent via USPS and may take up to 14 business days to process and arrive, depending on your normal postal service speed. For shipments to Canada, Hawaii, Alaska and Puerto Rico please allow up to 25 business days. International shipments may take longer depending on the location of the closest distribution center and shipping destination.

Will I receive tracking information on my Free-Parts-For-Life shipment?

Free-Parts-For-Life Program shipments do not include tracking information. After making your parts request online, you will receive a confirmation message and your parts will be shipped in 2-3 business days from placing the request.

How do I put a replacement diaphragm and retaining ring on the chestpiece?

Take your new retaining ring with the diaphragm installed and with the MDF Instruments logo facing up, place it on top of the diaphragm side of the chestpiece. Using your thumbs, slowly work around the edge of the ring to push it down and over the edge of the chespiece to fit snug. You may hear it snap into place. Inspect the chestpiece to make sure the diaphragm does not have any gaps or isn't popping out from the edge of the retaining ring. Feel free to watch this video showing the process.

How do I take the diaphragm and retaining ring off the chestpiece?

Remove your existing retaining ring and diaphragm by pressing the retaining ring down towards the chestpiece with your thumbs until it pops off. This video demonstrates the process.

How do I put a replacement non-chill ring on the chestpiece?

Take your replacement non-chill ring and start by fitting the edge of the ring around the bell of the stethoscope. Using your thumbs, work around the ring to stretch it over and down the bell. Check out this video showing the process.

How do I take the non-chill ring off the chestpiece?

To remove the non-chill ring, push the edge of the ring over and down the bell of the chestpiece. The entire ring should stretch over and off the bell. Click here to watch a video that will walk you through the process.


Can my stethoscope be engraved?

We offer custom engraving on the chestpiece for select stethoscopes ordered from our US website. You will see the option to engrave on the product page for any model that applies.

You can also check with your local jeweler who offers engraving. Engraving the stethoscope chestpiece will not effect the sound quality or the Lifetime Warranty if engraved properly.

How do I clean my stethoscope?

We recommend using 70% isopropyl alcohol pads or on a cotton ball or swab, to clean the eartips and wipe the diaphragm and chestpiece of your stethoscope. To clean the tubing, use warm water with mild detergent and a clean rag or towel to wipe the stethoscope tubing and dry. Do not soak the chestpiece or allow liquid to enter.

What can I do if my white tubing has become discolored?

Due to the nature of the material of stethoscope tubing, it can easily pick up dyes from scrubs or pen ink and become stained. If you have tried cleaning the tubing and your stethoscope has become permanently stained, please feel free to contact us and we will try to find a solution that meets your needs.

What warranties does my stethoscope have?

All MDF Instruments Stethoscopes (excluding the single-use line) come with a Lifetime Warranty and Free-Parts-For-Life Program. If you are experiencing issues with your stethoscope or would like to order new parts, please contact us or register and submit your request online here.

What do I do if my eartip tears or breaks?

Do not worry because we are happy to send you more at no cost, as part of our Free-Parts-For-Life Program. We offer replacement eartips in clear and black in three sizes (small, medium and large).

What if I can’t hear out of my stethoscope?

There are a few things you can check if you can't hear out of your stethoscope. First, check that the diaphragm is securely attached to the chestpiece with no gaps between the retaining ring and forms a tight seal like a drum. Make sure the chestpiece is rotated so that the green dot indicator on the stem if facing the side of the chestpiece you would like to use. Next, check that the pre-angled headset is facing forward so that the eartips are in line with the natural angle of your ear canals. Check if any part of the headset feels loose or broken inside of the tubing or if there are any punctures or tears in the tubing and it feels flexible and soft. If you are still not able to hear of your stethoscope, don't hesitate to contact us.

What does the green dot by the chestpiece mean?

The green dot located on the stem of the chestpiece will indicate which side of the chestpiece is active. The stem will rotate to the diaphragm or bell side with the green dot indicating the open channel.

How do I know if it’s a dual head stethoscope?

A dual head stethoscope will allow you to listen to both high and low sound frequencies. All MDF Instruments Stethoscopes will feature a True Bell and a True Diaphragm to consistent and easy auscultation. The bell side is designed to pick up low frequency sounds and the diaphragm side of the chestpiece is designed for high frequency.


What do I do if my sphygmomanometer is leaking air?

If your sphygmomanometer is leaking air, it could be possible that the connections have loosened. Check the connection from the tubing to the gauge to make sure it is secure and the end of the tube is flush with the gauge. Also check the connection from the tubing to the bladder of the cuff to make sure it is secure and no air can escape. Next check the connection from the tubing to the bulb and make sure the end of tube sits flush with the metal end of the bulb.

Fully inflate the cuff and listen for a hissing sound. This could indicate an air leak. Check for punctures in the bladder, tubing and bulb. If you think you have an air leak, please contact us to place a Lifetime Warranty request. You may register your instrument and make the request online using our online registration and service form.

What do I do if my sphygmomanometer won’t deflate?

Check that the valve release on the gauge is working properly and will allow for a release of air when turned open. If this is still not working, please let us know by contacting us directly.

How do I know which cuff size I need?

Using the wrong patient blood pressure cuff size will likely yield an incorrect blood pressure reading. All of our sphygmomanometers will come with an adult sized cuff, but we also offer the following cuff sizes separately, so you can ensure blood pressure reading accuracy.

Upper Arm Circumference Ranges by Cuff Size:

Thigh: 40CM - 65CM (thigh or upper arm)
Large Adult: 33.5CM - 50CM
Adult: 25CM - 40CM
Pediatric: 19CM - 27.5CM
Infant: 14CM - 20CM
Newborn: 10.2CM - 16CM

How can I clean my cuff?

To clean your blood pressure cuff, remove the bladder, then wash with warm water and mild detergent. Allow to air dry before replacing the bladder. Bladders can be cleaned with a rubbing alcohol solution and clean cloth.

Reflex Hammers

What do I do if the handle of my reflex hammer is broken?

Please contact us to see if you qualify for a Lifetime Warranty replacement. We would be happy to send you a new reflex hammer. You may complete the registration and Lifetime Warranty process online or contact us directly.

What do I do if the mallet of my reflex hammer is broken?

All of our reflex hammers have a Lifetime Warranty, so please contact us with a photo of your reflex hammer and let us know how this happened! You may also complete the Lifetime Warranty request and registration online.

What do I do if I lose one of the silicon mallets or it breaks?

You may qualify for a free replacement silicon mallet, included in our Lifetime Warranty. Please register your reflex hammer if you have not already and submit a Lifetime Warranty request, using our online registration and service form. Feel free to contact us for help with this process.


What do I do if I receive my penlight and it’s not working?

First verify that your penlight has working AAA batteries installed. If you replace the batteries and it's still not working or it has a defect not associated with the batteries, please contact us directly.

Does my penlight have a warranty?

MDF penlights are warranted to be free from defects in material or craftsmanship. Penlights with defects in material or craftsmanship will be replaced or repaired without charge as long as the defect is reported within one year of the original purchase. The MDF® 621 LUMiNiX is warranted to be free from defects in material or craftsmanship. LUMiNiXes with defects in material or craftsmanship will be replaced or repaired without charge as long as the defect is reported within two years of the original purchase.

Other Questions

Are MDF Instruments products latex free?

Yes, all MDF Instruments products are 100% latex free.

Do you sell face masks, face shields, PPE and oximeters?

We do not sell face masks, face shields, PPE and oximeters at this time.