Momo Special Mouthpiece. - Model: MMM 50 - Atelier Momo (Brass Lab) I have kept this in storage, having hardly used it. There are some minor scratches near the shank due to a habit of twisting it when inserting. Please check other sites for specifications, etc. It seems to be a collaborative development with Satoshi Murakami. Regarding the shank, there is no specific information about it, so it's unknown. However, it fits my Alexander and Yamaha horns without any issues, so I don't think it's something to worry about too much. There is a dent on the shank end. You can see it in the photos. I haven't used it much, so I left it as is without repair. This is being sold with the understanding that the buyer will take it to a musical instrument store for repair. I have discounted the price to reflect the cost of the repair, so thank you for your understanding. If you are concerned about the dent, please refrain from purchasing. Please consider the above points before making a purchase.