We are offering FREE 5MM Mouthpiece fitting sessions
when you visit our Denver, Colorado showroom
We no longer offer exchanges or returns on shipped 5MM kits and components

5MM Rim Size Reference: Trumpet, Cornet, Flugelhorn
The 5MM Modular Mouthpiece is available in every single size allowing you to duplicate the parameters of any brand/model mouthpiece and combine them with other sizes. For instance, you may prefer the feel of a specific brand/model rim such as a Bach 3C. The 5MM equivalent is the to a Bach 3 rim is the 812.614 which may be combined with any cup, throat and backbore to create your own custom mouthpiece configuration.

How do I order a specific size like a 3C?

1) Choose Rim 812.614, which is in the same row as the 3 diameter
2) Choose Cup 614FA, equivalent to a C cup
3) Choose Throat F145.21, equivalent to a standard 3 Throat
4) Choose Backbore 21.35, equivalent to a standard 3 Backbore
5) Choose your Body style
6) Choose your Nut style

You want to order a different size? See the comprehensive cross reference chart below or just ask us and we'll get you started on your 5MM in a matter of minutes.

Need help with sizes and options? We're here to help.
Call us at 303.657.2747 or email harrelsontrumpets@gmail.com to discuss your needs with us.


Getting Started
The easiest way to get started in the 5MM System is to choose a Rim close to your current mouthpiece. To save you time and energy, you may order your 5MM by simply telling us which brand and size options you prefer and we will do all the cross reference work to get your mouthpiece built right the first time. It is not necessary to learn our sizing system.

1) Order based on your current size
2) Build your own size
3) Experiment with a full kit
  • 9 piece Kit - 6 playable configurations
  • 19 piece Kit - 120 playable configurations
  • Custom Kit - scan your personal mouthpiece
Understanding Size options

HT Size - this 6-digit number designates a specific brand/model rim that we have scanned or a created option
ID Top - First 3 digits, dimension of the ID top in thousandths of an inch, measured from the very top point of the Rim
ID Bottom - Second 3 digits, measured at the very bottom diameter of the Rim where it meets the Cup
Rim OD Shape - the outside curve shape which is often characteristic of a specific brand, W = wider version of original size
Rim ID Shape - the inside curve shape which is often characteristic of a specific brand, commonly not designated

Custom Order Options
You are welcome to create your own sizes. It is possible to start with features from one size and combine them with another size within the Rim, Cup, Throat and Backbore. We recommend matching diameters between each component for best results. All custom orders are individually designed and machined, which requires a minimum of 2 weeks to produce before plating.