This is an accessory that came with the trombone I purchased about 5 years ago. There were two mouthpieces, so I never used this one and kept it in storage. YAMAHA trombone mouthpiece. Standard series made of brass with silver plating. It has a well-balanced rim and cup with a narrow back bore, and is standard equipment on the YSL-820GII. Large shank. ■ For trombone/euphonium ■ Large shank ■ 48 ■ Rim inner diameter: 25.25mm ■ Throat diameter: 6.62mm