Kelly Mouthpieces Small Shank Trombone 12C Mouthpiece Jet Black Small Shank Trombone 12C Mouthpiece Jet Black Kelly Mouthpieces are made of Lexan polycarbonate material that provides comfort in hot or cold weather gigs This means less fatigue on your chops They are great for Marching Bands, Pep Bans and Festive occasions Kelly Mouthpieces are made of Lexan polycarbonate material that provides comfort in hot or cold weather gigs