Austin Custom Brass Lead 1 trumpet mouthpiece, standard series, outer rim diameter Ø 26,92mm (1.06"), inner rim diameter Ø 15,93mm (0.627"), cup shape: Very Shallow Bowl, relative cup depth: 3, backbore shape: A2, silver plated, closest equivalent: Yamaha Bobby Shew lead, Marcinkiewicz Bobby Shew 1 or Giardinelli 10S