This is a rare mouthpiece with a trombone-sized rim but a trumpet-sized shank. Trombone and euphonium players often find it difficult to play the trumpet due to the size difference, but this mouthpiece allows them to play without feeling awkward. Conversely, it can also be used for practice by trumpet players who want to play the trombone. Rim inner diameter: 24.4mm, Throat diameter: 4.5mm I have stored this mouthpiece after hardly using it after purchase. It has some minor tarnishing due to personal storage, but it is in relatively good condition. The original price was around 36,000 yen, but I have lowered the price considering that it doesn't have a box and is used.