B.E.R.P. (Buzz Extension and Resistance Piece: バープ) is a practice aid kit loved by over 50,000 brass players worldwide. It's easy to use: simply attach the BERP and mouthpiece to the mouthpiece receiver. You can buzz while moving the rotary valve, just like when playing. This allows you to not only practice buzzing, but also to practice fingering efficiently and effectively at the same time. This is a rather unusual model.