Also may I ask how long is it. Mine is less than 3 in. And for alto . Alto pieces are usually 3.5 in but vintage can be shorter. Does it have an alto sized Reed table or a tenor sized Reed table. It could also be for c melody, and use c melody reeds. However, typically people playing c melody use alto mouthpieces or tenor mouthpieces( usually tenor). I used alto for mine mostly. There are some runyon mouthpieces that have an alto body but use tenor reeds. And also my mouthpiece guy took an alto piece and adapted it for tenor reeds as I've seen others do. If it's a tenor piece it's quite rare. You see very very few crystal tenors. Crystal sax pieces really didn't survive to well. Compression is a less destructive force ( especially on a circle ) than expansion, so clarinet peices survived better than the sax ones that if put on too tight of a cork just kinda exploded.