This is a Laskey 30C, gold-plated finish. For F tuba, American shank, shallow cup. [Plating Wear] - Shank - Outer cup (as seen in the second photo) There are no dents or distortions on the shank, backbore, or rim, so there is no problem with playing. I bought it on Mercari, but unfortunately, it didn't suit me well, so I'm listing it in case someone else needs it. Below are the catalog values. Rim inner diameter: 32.89mm Throat diameter: 7.49mm Since the rim inner diameter is the same as Laskey 30H and 30G, it might be a good mouthpiece for those who are concerned about the rim fit when switching between B♭ and C tubas. This is a used item, so please understand that before purchasing.