This is a Shires vintage 2G trombone mouthpiece. I bought it new about a year ago and used it for about four months, but it didn't really suit me, so I haven't used it since. It's in pretty good condition since I didn't use it for long, but there are some strange, spot-like stains if you look closely. There's also a scratch on the rim's side. Rim outer diameter: 39.15mm Rim inner diameter: 26.80mm Throat: 7.00mm I think it's suitable for a bass trombone. Price negotiable.