This is a rare hard rubber Dukoff Mouthpiece with the Fluted Chamber. It has a BD facing. It measures a precise 0.105. 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.