Standard Mouthpiece I am also selling this as a used item, so I am offering it at a low price. Recommended for everyone, from beginners to advanced players looking to revisit the basics. BB-67C4: This model is perfect for Bb and C trumpets, and is an all-around type. It produces a consistent, calm sound with a rich, powerful volume. Rim Inner Diameter (mm): 32.06 Throat Diameter (mm): 8.10