Thank you for viewing. This is a WI&FI bass clarinet mouthpiece. The model is ZF. I purchased it new last December and used it 2 or 3 times. I personally felt that the low register produced a very deep sound. It's made of V-Quartz, not ebonite, so it won't discolor even if stored with the instrument. I will clean it lightly before shipping. I may cancel the listing if it doesn't sell. As this is a used item, I look forward to your purchase if you understand this.