Hammond Design 21BL SP Hammond Design 21BXL SP Bass Trombone Mouthpieces Hammond Design 21BL & 21BXL (both silver-plated) Bass Trombone Mouthpiece Set of 2 Suggested Retail Price: ¥37,400 each The 21 rim is equivalent to Bach 1/Schilke 60. The BL model has a larger inner rim diameter and cup depth. It has a bowl-shaped cup with a tapered throat entrance, which is funnel-shaped, providing excellent breath support while maintaining the controllability of a shallow cup. The BXL model has a similar cup shape (bowl-shaped) to the BL model, but the depth is very deep. This is a big boy! Inner Rim Diameter (Cup Inner Diameter): 29mm (1.140") BL...Standard depth mouthpiece. Easy-to-control bowl shape. BXL...Deep bowl-shaped cup. Open blowing feel, but requires a lot of air. I have been using 29mm size mouthpieces for a long time, and I decided to sell these mouthpieces of the same size together after downsizing. Both have been used, but they are in very good condition and have no accident history. There are no original boxes. Currently, there is no plan to sell them separately. I am also listing other mouthpieces of the same size, so please take a look from this tag. #29mmBTBMP Type...Trombone Accessories/Parts...Mouthpiece Level...Advanced