This is a rare hard rubber Dukoff Mouthpiece with the Fluted Chamber. It has a BD facing. It measures about 0.100".
This piece is in excellent near mint original condition with no wear on the biteplate and perfect table, rails and tip.
This piece has a very cool sound and feel. It plays similar to an early Babbit hard rubber Link with a bit more projection and focus. This is a unique and great sounding vintage mouthpiece.