Thank you for viewing. This is a YAMAHA 18B4 NC mouthpiece, the model for Mr. Yoshihiro Nakagawa. Made at the Yamaha Atelier, this model was developed by Mr. Yoshihiro Nakagawa under strict standards, assuming use on stage for performances. 【Specifications】 ・Inner rim diameter: 17.42mm (slightly larger than Bach 1C) ・Rim shape: Semi-flat, standard thickness ・Cup: Slightly shallower than Bach C ・Inner rim edge: Beveled. Designed to prevent the lips from touching the inner cup wall, making it less tiring even during long performances. ・Throat: Slightly narrower than #28 (3.57mm) ・Backbore: For classical music. Comparable to between Warburton No. 9 and 10. ・The outer rim edge is gentler than Bach 1C, recommended for those who find 1C too large. There are minor scratches from use, but there are no issues with playing. Please check the photos for details. It will be carefully packaged and shipped promptly. If you have any questions, please feel free to comment.