Hammond Design 4ML Trumpet Mouthpiece

I used this mouthpiece for about half a year, but I'm selling it because I've started using a different one.

Rim inner diameter: 16.81mm
Cup: MD
Throat: 25
Backbore: #4

I believe this is roughly equivalent to a 1-1/2c in Bach sizing. It's a very popular size. It performs very well on the C trumpet, but I felt it was an even better match for the B trumpet.