This is a Yamaha 14B4 trumpet mouthpiece. It was included new with a new D/Eb trumpet I purchased and has been stored without ever being used. I am selling it because I have no use for it due to its size. <Quoted from the official website> Cup Volume: B Inner Diameter: 16.85mm Throat Diameter: 3.65mm Description: A combination of a slightly large rim diameter and a slightly shallow cup. It is highly refined and has the ability to meet the advanced demands of top players. Reference New Retail Price: 6380 yen