New Proprietary Brass Alloy
Flex mouthpieces are made using our proprietary Bellflex brass alloy. This alloy has extremely resonant properties and is integral to the design of our Flex mouthpieces. Check out the testimonials here.

Two Series of Flex Mouthpieces are Available
VR Series Sizes: [1], [1.5], [3], [5], [7], [10.5] and [12]
Traditional Series Sizes: [1], [1.5], [3], [5], [7], and [12]

Traditional Series Description
The Traditional Series function similar to vintage Bach mouthpieces but with an improved sound and scale.
Choose your Traditional Series Mouthpiece here.

VR Series Description
The VR Series use our new cup and backbore balance. They produce a bigger sound with more low frequencies and are considerably easier to play.
Choose your VR Series Mouthpiece here.

Choices Available
Both series offer different backbore choices and are available as solid shank or cut for BellFlex Couplers which allows you to adjust the gap from the end of the mouthpiece to the start of the leadpipe.

Most existing mouthpieces can be redesigned to have a VR cup and backbore balance that will produce a bigger sound with more low frequencies and be easier to play.

Technology Merged with Tradition
All Flex Mouthpieces are made using a combination of CNC machining and hand balancing.

Many Sizes Available
Choosing the correct mouthpiece is a very personal endeavor. Feel free to contact us with any questions or concerns and we'll do our best to help you in your quest.

Mouthpiece Construction Illustration

K.O. Analyzing mouthpieces

Flex Mouthpieces and BellFlex Couplers (click for larger view)

Testimonials:

My new S13A mouthpiece is fantastic! Very efficient and easy to play, but with great core and a full range of overtones in the sound. The day after I got my mouthpiece I had a rehearsal and the sax player commented how good I sounded. "New mouthpiece" I told her! It works very well with my Stomvi Elite Trumpet, a great instrument for any style of playing, from classical to lead.

Frank Abrahamson, freelance
formerly with: Maynard Ferguson
Wayne Newton, Branson MO shows

Wow! I can’t remember when I have actually been excited about a mouthpiece!

Flex mouthpieces are highly efficient, very easy to play with rich overtones, bigger sound, better attacks, great intonation and focus with a fantastic upper register, all with less effort!

If you really want to improve your playing…Flex Mouthpieces will help you get the results you're striving for.

Thanks K.O. for all of your help and especially for making such a great mouthpiece!

Scott Wiltfang--Freelance, Chicago

All the best,
Scott Wiltfang
Calicchio DT s1s/3M
Calicchio 1s/2rM
Yamaha 6310Z Flugelhorn
Jean Baptiste VT480B Bb Valve Trombone
Flex JM VR mouthpiece

When I first tried some of K.O.s prototype Flex mouthpieces I was so knocked out by them I gave him my spare mouthpiece and told him if you can put your VR twist on what I already have, DO IT!

We discussed what I would want. We knew the rim and cup style I needed and he nailed it the first time!

Everyone I have played this mouthpiece for has picked it out in a blind fold test. My custom Flex mouthpiece has more core and vibrancy to the sound, better projection, better intonation, and a more even scale in every register of the horn. I am getting more sound, with less effort!

I have not tinkered with mouthpieces in years. This time I'm glad I did!

Michael Manthey - Freelance California
Maynard Ferguson BBN Band

I had my first lesson with the new Flex 3D VR Vs mouthpiece today after playing/loving it about a week. I decided not to tell my professor about the new mouthpiece just to see if he would notice. I finished playing a Charlier and his first comment was, "Wow...your sound is a lot bigger" That did it for me. I already loved the richer sound and ease of play so hearing an honest, blind compliment from my teacher really locked it in. Thanks for making a mouthpiece that gets me a better sound with less work than before...I'm having a ton of fun!

Andy Sites
Henderson University, Arkansas

"I have been working with K.O. since 1996. I respect his knowledge and expertise on the art of making trumpet mouthpieces. I have been playing the 3F VR for commercial and 3C VR for legit playing since April and am loving the sound I am getting with these mouthpieces. They add a unique dimension to my sound that other mouthpieces could not produce. Kudos to K.O. and his hard work!!"

Chris Hammiel,
USAF Heartland of America Band

"I received my Flex 14A mouthpiece with my 43N rim from you last week, and have been using it on gigs and the difference is incredible! More overtones, richer sound, clearer attacks, a lot more projection, better intonation, and an evenness from soft to loud that I have never been able to get before. I had a colleague over last night, and A-B'd this new Flex piece against the mouthpiece I've used for the past 3 years. There is no comparison. I thought my previous mouthpiece was great; the Flex 14A is even better! I am getting more sound with less effort. I will be ordering a Flex 3C for my legit work, and a Flex 13A for more demanding lead playing. Thanks to you and Jim for putting on that master class at Thompson Music in Omaha this past April. I have been applying the techniques you taught me, and am already playing with less tension and getting greater results.

Thanks again for all your help."

Mike Supple
Freelance - Minneapolis/St. Paul

"This is it! I've boxed up all my other mouthpieces and put them in the attic. After spending thousands of dollars on every mouthpiece known to man, I've found one that works. For years I've been struggling with lip swelling, flexibility and sound issues mostly due to muscling the mp. From the first sounds that I made with the Flex, I knew there was something special and different about this piece. The first thing I noticed was the HUGE sound coming out of my horn, the second thing was the evenness from low to high, the third was the improved intonation and the fourth thing (after a couple of hours) was NO lip swelling. I've finally found a mp that I can relax on and still produce a huge sound with less effort. I have the 7D VR Vs and am ordering the 7F VR Vs for my more demanding lead work."

Jeff Strahlem
Lead Trumpet
Air National Guard Band of the Central States

"I was up at Thompson Music in NE. I did purchase your Flex mouthpiece. I bought your S14A VR and it is fantastic. He was out of your raptor trumpets a couple weeks ago. I'm just a part time player but really enjoy the mp. Thompson Music was very helpful with your products. I get so much color from this piece, improved articulation, and lastly it is very easy to speak at all dynamics."

Warren Lopicka
Liberty, MO

"Hey KO- regarding the 12f vr vs.

I could hear the darker sound qualities on this new one right away even though the rim is as small as it is.

Depending on how I push it, the sound is able to be whatever the job calls for. I used it to play a gentle, full sound for taps at a military ceremony, a compact warm sound for small group jazz, and it nails the lead parts with accuracy and full, powerful tone.

I believe the psychology of being free from the usual compensations, endurance and response limitations is going to cause some to feel like a "fish-out-of-water". You may need to develop an adjustment procedure/profile on your web site to help people cope with the realization that much of what they were taught about mouthpieces is wrong."

Tim Keleher
Freelance trumpet player - Philadelphia/New Jersey

"I have decided your are not just an artesian who creates horns and mouthpieces, you are a dealer (as in pusher) who services the neurotic/addictive needs of trumpet players. Your cunning plan is to just keep improving everything until all the trumpet players are in the poor house! You will be the only trumpet player left, and hence in high demand. Very clever in deed!

Thanks for the wonderful creation of the S13A VR Flex Mouthpiece. The mouthpiece plays great in the upper and lower range! What a rare thing that is. I am getting the best G ever."

Rob Williams
Lead trumpet - San Luis Valley Big Band in Alamosa, Colorado.

"I recently attended the Stomvi USA / Brass Spa seminar at the ITG Conference in Harrisburg, PA. I learned more about the trumpet and mouthpiece at this seminar than I had in several years of trying to educate myself. There was more real world information (stuff I can really apply) presented than at any clinic I've ever seen."

Thanks!

Jeff Helgesen
Freelance, Illinois

"The new Traditional Flex 1C with the #6 backbore is by far the best mouthpiece I have ever played. I fell in love with it immediately as it took zero time to adjust to it. When looking for a new mouthpiece I have always had to debate on what to sacrifice, sound or ease of playing. With this mouthpiece there are no sacrifices, it plays with ease in all registers with the biggest sound I have ever produced."

Tim Saeger - freelance trumpet player in San Diego

"The new Flex 1.5C Vs gives me more core and guts to my sound without losing the brilliance I need. I also do not need to open up the throat to get that big sound I want, so it remains very efficient. It is extremely responsive (I also do not feel that I need 'forever' to warm up... It just works really well really quickly). I have gotten a lot of compliments on the tone. The response, control, and intonation all enable me to play more easily. This mouthpiece makes it more intuitive for me to achieve the sound I have in my imagination when I play."

Karl Sievers, DMA
Professor, Chair of Brasses, School of Music, University of Oklahoma
Principal Trumpet, Oklahoma City Philharmonic

"The new Flex mouthpiece is an amazing development on the part of K.O. at the Brass Spa.

I have been playing on the Traditional Flex 1C with the #6 backbore and found it to be very in tune, slotted, and even through all registers. The sound is big and rich with sparkle. The colors work so well in the orchestra fitting in with the strings, winds, and brass, and I have found that to be one of the biggest challenges playing in an orchestra.

I would highly recommend the Flex mouthpiece to anyone looking for a tool that gets the job done and makes you sound great doing it.

Thank you again K.O. for making my life easier and more enjoyable.
Keep up the great work"

Frank Glasson - freelance trumpet player in San Diego

"I've been playing on a Flex prototype for a few months now and the thing is amazing - I am getting more sound with less work -

KO made my last Reeves custom and I doubted that he could top that - but when he sent me a Flex to try - I thought no way - I'd rather change girlfriends then my mouthpiece -

I played both of them on my gig that night and there was no comparison -

I saw the same reaction at a the clinic we did in Omaha - people were astounded at the sound they were getting out of the mouthpieces."

Jim Manley - Freelance, St. Louis

"Now that my "honeymoon phase" is over with my new Flex VR mouthpiece; I thought I would share my thoughts with you regarding it. To be very honest with you; when I first saw your Flex VR mouthpieces at this year's NAMM Show, it certainly was not love at first sight. After using "tone intensifiers" and "mega" heavy mouthpieces I thought..."These look like boring traditional mouthpieces so I doubt if they could create any magic for me". Well, after a few blows, I was wrong! The sound was perfectly rich without being dull. I validated this by also listening to raw (no effects) recordings of myself in order to better understand the sound from the other side of the bell. I then found that even though it had a nice full color to its core sound and warm tone, I did not have to sacrifice playability and response in the higher register. When I played it (along with many other well known branded mouthpieces) during a blind test with my overly honest Wife, she responded..."That one makes you sound like a professional!" On a separate note, your expertise and customer service is truly amazing! I remember after you asked me several questions (while fitting me with one of your mouthpieces) it was the FIRST mouthpiece you recommended that fit me the best and the one I purchased! Even though I played several more of them, I kept coming back to that first one! Your straight forward, patience, and respectful approach with me showed your true commitment to ALL Trumpet players (not just professionals) and your passion for the optimization of the ever elusive "equipment plus player" equation. In closing, I would like to say that I am 100% confident that your great Flex VR mouthpiece has finally ended my (25)+ year "mouthpiece safari". If someone welded it onto the receiver of my horn, I wouldn't be the least concerned! Thank You & Congratulations on designing and manufacturing what I strongly believe is the best mouthpiece I have ever played!"

Dan O'Donnell