Soft, molded material. Inside rails fit snugly against mouthpiece. Will not scratch your mouthpiece. Will not crack or chip if dropped. 
 
The D'Addario Bass Clarinet mouthpiece cap is made of flexible material and features rails that fit snugly against the mouthpiece. That way, if you accidentally drop your mouthpiece cap, it will not break or chip
 
PRODUCT FEATURES
Type: Filed
Traditional blank and profile, filed cut
Ideal for beginners
Designed for ease of play
Priced affordably for educators and parents
All D’Addario reeds are designed and manufactured in the USA from naturally-grown cane