This is the Schaller Swirl trombone mouthpiece! It is a small shank mouthpiece used for trombone and euphonium that I designed myself, and it features a pretty big cup to get a deeper tone and really blow out some lower notes. The swirl design on the cup is a unique aesthetic that you will not find on many other models, although it may require a slightly beefier 3D printer to print precisely. Measures out to 38x38x85mm with a variable bore size that would most likely also fit some smaller large shank horns. Hope you enjoy the mouthpiece and happy playing!