The JK (Jet-Car) thin-tube mouthpiece, model number Exclusive 9B. The rim is equivalent to a 7c size, and the cup is equivalent to a 6-1/2AL size. Because the cup is equivalent to a 6-1/2, it produces a deep and mellow sound. However, the rim is equivalent to a 7c, which is smaller, making it easy to maneuver. Despite the sound it produces, as a player, I felt it was a compact and agile mouthpiece. As is typical of the German manufacturer JK, the precision is also excellent. As the photos show, the condition is very good.