This is a Vincent Bach trombone large shank mouthpiece, model 6 1/2A. It was used for a year and a half, so there are minor scratches and imperfections from the coating process, as well as marks from inserting and removing the shank. I had a custom resin coating done by a company called UPMAKE, specifically the ReSTM2 process. This is the modification shown in image 5, section ③. This is recommended for those with metal allergies or for playing in the winter.