The YBH301M Series features a .571" bore designed for a large, full sound, plus a large shank mouthpiece for a more natural feel to your euphonium players on the field.
 
FEATURES
Key: Bb
Bore: .571-inch
Bell: 10-inch
Bell Material: Yellow Brass
Valves: Nickel-Plated Pistons
Features: Gold Brass Leadpipe; Large Shank Mouthpiece Receiver; Heavy Bracing
Case: Yes
Mouthpiece: Yamaha L48 Large Shank
Finish: Lacquer, Silver 
 
This particular horn is in fantastic shape. It appears to have been played rarely. Comes with mouthpiece, case, valve oil, polishing cloth, and manual. Serial number is 332372. The valve action is fast and effortless.