Marcinkiewicz 307 vs Marcinkiewicz 309
Both mouthpieces share similar core dimensions — the differences are in the details.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Marcinkiewicz 307
• Cornet
Cup diameter17.20 mm / 0.6772 in
vs
Mouthpiece B
Marcinkiewicz 309
• Cornet
Cup diameter17.20 mm / 0.6772 in
Cup Diameter
Both mouthpieces have virtually identical cup diameters at 17.20 mm / 0.6772 in.
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.