PHC horn mouthpiece, the cup is a 23A and the rim is AN. The cup is probably solid nickel, but there's no guarantee. The cup is old, so it's solid and shows its age, but there are no scratches other than dents and shank wear. The rim is gold-plated and beautiful. Sold as a set only, not for individual sale. Specs are as follows: Cup: 23A Depth: medium Bore diameter: 4.70mm Rim: AN Inner diameter: 17.5mm Rim width: 3.75mm The depth is medium according to the catalog, but I think it's deeper than a typical mouthpiece. The bore is large, so it requires a lot of air, but it has a unique, encompassing tone that's different from other mouthpieces. The rim shape is flat and thin, making it comfortable on the mouth. It feels slightly larger than other manufacturers' 17.5mm inner diameter rims.