Vincent Bach
The world's most referenced brass mouthpiece system. Bach's number–letter code has become the universal measuring stick for cross-brand equivalency and player communication since 1922.
Choose your instrument
Bach Trumpet Guide
The Big Three (3C / 5C / 7C), Artisan series, model number decoder, full dimension table, and equivalencies for Schilke, GR, Warburton and more.
Read the guide →Bach Trombone Guide
Small shank vs. large shank, the G-series explained, bass trombone models, and shank dimensional specifications for proper instrument fit.
Read the guide →Quick Reference
Bach Number–Letter System at a Glance
1 (largest) → 20 (smallest). The number alone defines the rim inner diameter.
Omitted = deep, C = medium, E = shallow. Modifies the cup volume.
W = wide rim. Improves endurance, reduces flexibility slightly.
Standard. Gold (GP) is an extra-cost option across all models.