Standard Series Bass Trombone Mouthpiece 4. Designed for the player whose needs are not met elsewhere, the Standard Series Large Shank Trombone Mouthpiece in Silver affords enhanced projection, even timbre from ppp to fff, and the same great intonation throughout all registers that Marcinkiewicz mouthpieces are famous for. They are optimized to give the player the best efficiency possible without compromise. The Standard Series mouthpieces are arranged in a logical ascending order from deep to shallow. This arrangement permits a player to select a mouthpiece by precise increments of depth to find the correct cup volume for their playing situation. As rim size does not directly correspond to cup depth, please observe inside cup diameter for finding optimal response. The comparisons are given for casual references only and are not exact.