Kelly 51D-EU-SS vs Kelly 5G-EU
the Kelly 51D-EU-SS features a deeper cup.
Mouthpiece A
Kelly 51D-EU-SS
• Baritone / Euphonium
ProfessionalCup diameter25.40 mm / 1.0000 in
Cup depth
Rim width—
Throat diameter—
BackboreL
Finish—
Material316 Surgical Stainless Steel
Best suited for
Orchestral playing — large cup for full, dark tone
Professional euphonium
vs
Mouthpiece B
Kelly 5G-EU
• Baritone / Euphonium
GeneralCup diameter25.40 mm / 1.0000 in
Cup depth
Rim width—
Throat diameter—
BackboreL
Finish—
MaterialLexan polycarbonate
Best suited for
Orchestral playing — large cup for full, dark tone
Euphonium general use
Cup Diameter
Both mouthpieces have virtually identical cup diameters at 25.40 mm / 1.0000 in.
Cup Depth
The Kelly 51D-EU-SS has a — cup while the Kelly 5G-EU has a — cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Kelly 51D-EU-SS is described as 316 Surgical Stainless Steel, and the Kelly 5G-EU as Lexan polycarbonate. Material affects mass, warmth, and how quickly the piece responds.
Which is better?
The Kelly 51D-EU-SS is designed for professional playing, while the Kelly 5G-EU targets general use. Your best choice depends on your musical context.