This is a Vincent Bach Corp. mouthpiece for a tenor trombone with a small shank. The size is 6-1/2. It's a mouthpiece from the so-called "Deep Period" made between 1970 and 1979. Compared to current mouthpieces, those from this period are characterized by their outstandingly rich tone and clarity. It's very easy to play. It shows some signs of use, but it can be used for playing without any problems.