5MM Nut options: Trumpet, Cornet, Flugelhorn
The 5MM Nut locks the Backbore in place and fills the external space between the Body and Receiver. 

Two diameters to match various Body styles

• 5/8" Cylindrical - transition to heavy style receiver and Harrelson R3 & R4 Venturi Gap Receivers
• 5/8" Tapered - transition to standard instrument receiver
• 3/4" Cylindrical - fits Harrelson R1 & R2 Venturi Gap Receivers
• 3/4" Tapered to 5/8" - transition to heavy style receiver and Harrelson R3 & R4 Venturi Gap Receivers
• 3/4" Tapered to 1/2" - transition to standard instrument receiver
  

Length options
The 5MM Nut is available in every length variation. We do not offer exchanges on Nuts as you will very likely find that the Nut originally supplied with your 5MM Kit will fit receiver variations in the future. To order the correct size Nut to completely fill your external gap, measure the nut from the body and measure the space between the mouthpiece and receiver. Do not make any adjustments to this number. We will reduce the length by approximately .005" to allow for error and wear over time for a perfect fit.

---