This is a Willie's U3 STEINER 5M SP mouthpiece for large-bore trombones. This mouthpiece is silver-plated and was designed under the supervision of Peter Steiner (International Soloist). Inner rim diameter: 25.5mm Throat diameter: 7.2mm Cup depth: Medium There are some scratches on the shank from insertion and small areas where the plating has come off, but otherwise, there are no noticeable scratches or stains, and I think it's in good condition. Please leave a comment if you have any questions or would like to negotiate the price. Thank you for looking.