Marcinkiewicz CH 303FL vs Marcinkiewicz CH 3FLB
The Marcinkiewicz CH 3FLB has a wider cup diameter, the Marcinkiewicz CH 303FL has a larger throat opening.
Cup Diameter
The Marcinkiewicz CH 3FLB has a cup diameter of 17.25 mm / 0.6791 in compared to 17.20 mm / 0.6772 in on the Marcinkiewicz CH 303FL — a difference of 0.05 mm / 0.0020 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
Both mouthpieces share a medium cup depth, so the sound character from depth alone will be very similar.
Throat Diameter
The Marcinkiewicz CH 303FL has a wider throat (4.32 mm / 0.1701 in vs 4.09 mm / 0.1610 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
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.