Kelly Mouthpieces are made of Lexan polycarbonate material that doesn't conduct hot or cold so it's perfect for playing outdoors. Made from Lexan polycarbonate/ABS, the same dimensionally stable material used in bulletproof glass. Won't dent shank or scratch rim if dropped. Produces less fatigue on players' chops and better endurance. Perfect for musicians who play outdoors as it doesn't conduct heat or cold. Kelly Mouthpieces are colored so you can play mouthpieces with your school colors, band colors, or favorite colors.