This is a horn mouthpiece from Brass Lab MoMo. It has a cup inner diameter of 17.3mm, a throat diameter of 4.3mm, and is a deep mouthpiece. It has been used for about a month, so there are some scratches on the shank. Although the inner diameter is a bit small, it's a mouthpiece that allows for smooth playing from low to high notes. The suggested retail price is 57,200 yen, making it an expensive mouthpiece, but I am selling it because I preferred a slightly warmer tone. I think it would be a good fit for those seeking a brighter tone.