This is a Giardinelli 5M mouthpiece for large-bore trombones. This mouthpiece can also be used on large-bore euphoniums. It is a 2-piece design. This is a so-called "old stamp" mouthpiece, with the manufacturer's name stamped as "GIARDINELLI NEW YORK". There are shank scratches and minor scratches from use, but there are almost no major scratches, and this condition is rare for an item of this age. Please check the photos for details.