Quick Comparison - The GR 3M is GRs answer to the very popular bach 3C mouthpiece. The 3M's closest true GR is a 66M but features a slightly wider rim giving a feel similar to the bach. Widley used for Bb,C and Eb trumpet work. As the trend in player is moving towards slightly smaller rims mouthpieces, this is becoming a very popular model.
Key - Bb,
.504” bore
Rose brass leadpipe
8 3/8” yellow brass upright bell
Top spru