Kelly 7C-BUGLE vs Monette B4S S2
The Kelly 7C-BUGLE has a wider cup diameter, the Kelly 7C-BUGLE features a deeper cup.
Cup Diameter
The Kelly 7C-BUGLE has a cup diameter of 16.51 mm / 0.6500 in compared to 16.20 mm / 0.6378 in on the Monette B4S S2 — a difference of 0.31 mm / 0.0122 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Kelly 7C-BUGLE has a medium cup while the Monette B4S S2 has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
Throat diameters are essentially identical at 3.66 mm / 0.1441 in, so resistance feel will be comparable.
Material
The Kelly 7C-BUGLE is described as Lexan polycarbonate, and the Monette B4S S2 as unspecified. Material affects mass, warmth, and how quickly the piece responds.
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.