Custom BT#1 Trombone Mouthpiece
Inner diameter: 1.123" or 28.524mm
Bore Size: Standard - .316" or 8.027mm, Symphonic - .323" or 8.204mm
Cup Depth: 1.533" or 38.938mm
This is a very large mouthpiece in every way.The BT#1 is only available on the heavy blank style. The extra mass really helps to lock down the core of the sound and helps to slot the pitch.