Tuba Mouthpiece from Mercer & Barker Ltd, Innovative by design, Inspired by sound.
Finished in Bright Silver Plate.
Model
Cup Dia
Throat
Rim
Comparison
MB1
32.5mm
8.30mm
8.00mm
Wick1/1L/1XL/K&G 1F/Conn7B
 
 
 
 
Bach 12 / Schilke 67 / 69C4
 
 
 
 
Perantucci PT34/70/72/80/82
MB2
32.0mm
8.50mm
7.80mm
Mike Finn MF3/Bach 7/PT88L
 
 
 
 
PT88/PT86/PT48+ K&G 1F
MBUZ2
33.50mm
8.30mm
7.75mm
Tim Buzbee Series
MB3
31.55mm
9.00mm
8.00mm
Bach 24AW / Wick 3/3L/3XL
MB3 “Power”
31.55mm
9.00mm
8.00mm
Deeper than the MB3, More focussed Sound
MBUZ3
33.20mm
8.30mm
7.90mm
Tim Buzbee Series
MB4
31.70mm
8.30mm
8.00mm
Slightly shallower than above
MBUZ4
33.50mm
8.30mm
7.75mm  Slightly flatter rim than the MBUZ2
MB4W
31.70mm
8.70mm
8.00mm
Larger throat than the MB4
MB5 “Cattanach”
33.00mm
8.30mm
8.00mm
Mike Finn MF3/Bach 7/PT88L K&G 1F
MBUZ5 Lonestar
32.80mm
8.20mm
8.55mm
Tim Buzbee go to F Tuba Mouthpiece, R2
MB6   “Goliath”
33.50mm
8.30mm
7.75mm
Largest Tuba Mouthpiece in the M&B, R1