Bach trombone mouthpiece 12C for small bore trombones. I am selling this to organize my mouthpiece collection. There are no scratches or dents, and it is in beautiful condition. This is an all-around mouthpiece that can be used for various purposes. Specifications: ■ Model: 12C (small bore) ■ Size: Inner rim diameter 24.5mm / Throat diameter 5.85mm ■ Plating: Silver plated ■ Will be shipped in the original box from when it was purchased.