Which has a bigger cup — Bach 5C or GR Technologies 66.5MS?

The GR Technologies 66.5MS has a cup diameter of 16.89 mm / 0.6650 in compared to 16.25 mm / 0.6398 in on the Bach 5C — a difference of 0.64 mm / 0.0252 in. A wider cup generally produces a fuller, darker tone but requires more air support.

How does cup depth compare between Bach 5C and GR Technologies 66.5MS?

Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.

Bach 5C vs GR Technologies 66.5MS

Name: GR Technologies 66.5MS
Brand: GR Technologies

The GR Technologies 66.5MS has a wider cup diameter.

Overall Comparison Cup Diameter Cup Depth Rim Width Throat Diameter Backbore Finish Material

Surface plating or treatment (e.g. silver plate, gold trim). Affects feel, durability, and appearance.

Mouthpiece A

Bach 5C

• Trumpet

Finish—

Best suited for

🎵All-round versatile — balanced cup for general playing

Mouthpiece B

GR Technologies 66.5MS

• Trumpet

Finish—

Which is better?

Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.