This is a mouthpiece I used over 10 years ago. It's a Tilz Schmidt model 55. I believe the inner diameter was 17mm. The Schmidt model has undergone several minor changes, so I recommend this to those looking for a model from this era. The condition isn't great. When I bought it used, there was hardened dirt inside the shank. I didn't mind it, but if you'd like, I can brush it with a polishing compound before sending it to you. (It has already been ultrasonically cleaned and brushed with a cleaner, and silver polish without polishing compound has been applied.) Please feel free to ask any questions or request additional photos in the comments.