This is a Willie's BOND 007 bass trombone mouthpiece. It is the signature model of Zachary Bond, former bass trombone player of the Malaysian Philharmonic Orchestra. Willie's Bond mouthpieces currently have several rim size variations, but at the time of purchase, this was the only size available. It was made to fit the Universal model of the instrument used by Mr. Bond, but it should also work well with Edwards and S.E.Shires trombones. Inner rim diameter: 28.1mm Throat diameter: 7.9mm Gold-plated finish There are some scratches on the shank and some blackening of the gold plating due to use, but overall it is in good condition.