This is the Yamaha Sergio Carolino model. I'm selling it because I bought a new mouthpiece. It has a shallow U-cup, which is generally considered suitable for F and E♭ tubas, but I used it with a C tuba (instrument used: YCB-822S). The sound became brighter and clearer. Sergio himself used it with a Yamaha York on YouTube, so there shouldn't be any problem. Please see the photos for the overall condition. There is a dent on the rim, but it hardly affects the playing feel. Please see the last photo for details such as the inner diameter of the mouthpiece.