This appears to be a mouthpiece purchased locally by a tuba player from a certain professional orchestra in Japan. It was purchased second-hand three years ago. This mouthpiece is for F tuba and has a large, resistant feel for an F tuba mouthpiece, and was even used on a C tuba for a while. It can produce a powerful low register even on an F tuba. The mouthpiece is engraved with "Prof. J. Nickel 328F". To help you understand the details, I have attached photos 5 and 6 from the Schmidt website, which are likely of this model. From left to right, the photos show the outer diameter, inner diameter, and cup depth of the mouthpiece! Photo 3 shows a dent in the shank that was present from the time of purchase, although it's difficult to see. Photo 4 shows a dent in the body that was present from the time of purchase. There are other scratches as well, but they don't seem to significantly affect the performance. The following is a quote from the website describing Schmidt's characteristics: "W. Chr. Schmidt" is a long-established mouthpiece maker that is particular about the metal used in its mouthpieces and carefully crafts each one using traditional casting methods. Its rich, elegant, and brilliant sound will captivate you.