This is a Parke trumpet mouthpiece, model 640R6-285-24. It's a one-piece design. I personally imported several mouthpieces with different model numbers, but I'm selling this one because I only tried it out and haven't used it. Inner diameter: Approximately 1•1/2C Rim shape: Mount Vernon Bach (according to Parke) Cup: 5B Throat: 24 Backbore: Orchestral (slightly larger than Bach's Symphonic 24) Purchase price: Approximately ¥45,000