This is a mouthpiece for a bass trombone made by Willie's. It came with a used instrument I purchased, and the model is Walküre TN0. I couldn't find any detailed information about it, so the specifications are unknown. It feels a bit larger than the TN catalog specifications. The shank number is 3. I've only tried it a few times since I bought it, so I think it's in good condition. Please note that there is no box.