This is a mouthpiece from Tilz, a well-established German mouthpiece manufacturer and a leading name in Europe. Inner Diameter: 17.5mm Bore Size: 3.8mm Cup Depth: Medium Rim: Medium Wide This mouthpiece has a balanced design, suitable for all-around playing from high to low registers. It's perfect as a first mouthpiece for junior high and high school students. I bought it to reset my playing with a standard model, but I only used it a few times and it's been in storage since. There are no dents from dropping it, but it is a used item, so please understand that there are some scratches on the shank. The shank is American shank. It fits Yamaha, Holton, Conn, Hans Hoyer, Wenzel Meinl, and other similar brands. Thank you for looking.