This mouthpiece is a collector’s item but it can very well be used for playing, although I would recommend plating it first. It has a shallow cup and cushioned rim. cup diameter is about the same as a 10 1/2C Bach. It seems like it was gold plated. The throat looks like it is a 27. The more I look at this mouthpiece I realize that it’s a great mouthpiece. Not really different than a lot of the mouthpieces out on the market today. This is an original.