KELLY Cornet Mouthpieces are made entirely of Lexan material. The 3C, and 7C cup sizes are patterned after the Bach series. All cup sizes are sampled by Kelly's professional staff and are adjusted to produce their final, comfortable, easy-blowing mouthpieces. Kelly mouthpieces are identical to exacting standards.
FEEL the Comfort!
Cup Diameter: .67"
Cup Depth: .55"
Inside Diameter of Receiver: .39"