B.E.R.P. (Buzz Extension & Resistance Piece) for Trombone. This is the original metal one.
Made in USA. Patent Pending 1986.
This is a practice device. It's meant to strengthen your embouchure, improve relative pitch, add resonance and range.
Comes with a sheet of warm-ups, range exercises, and practice suggestions.
This is new in a box. The box has been beaten up because we used to have this in our showcase in our music store, and would take it out of the box to show people.