This is a YAMAHA bass trombone mouthpiece. It was included when I purchased the instrument. Unopened, unused, and in good condition. ★ Immediate purchase is OK. ★ Please refrain from price negotiations. [Product Description] "BL-61D4L" The deepest cup among Yamaha trombone mouthpieces. The exterior is also a medium-weight type, and it is a mouthpiece that responds well to playing at high volumes. Rim inner diameter: 28.72mm, Throat diameter: 8.00mm, Rim contour: Slightly flat, Rim thickness: Slightly thin, Cup depth: Slightly deep Thank you for viewing.