This is a listing for a Silky mouthpiece, known for its refined design and brilliant tone. The 51 is equivalent to a Bach 5GS mouthpiece. With its characteristic sharp rim and long shank, this mouthpiece, while being a larger size for a small-bore, offers clear articulation and focused intonation, making it easy to control. I used it for lead playing in a big band. There are shank marks, but it is generally in good condition.