Vincent Bach trombone mouthpiece. Rim and cup shape similar to 6 1/2A. Features a larger G throat (6.63mm) and a #420 (dark) backbore. Produces a powerful yet mellow, rounded tone. Popular model among euphonium players. Silver-plated finish, large shank. This is a trombone mouthpiece I used during my student days about 10 years ago. I used it for 3 years. It has been cleaned. Please consider this item if you don't mind it being a used product.