This Stone Lined Practice mute is durable and inexpensive. Also refered to as the Mannie-Klein Sh! Sh! mute. "Practice anywhere-in a hotel room, motel room, studio or band room-even in the same house where a baby is sleeping. Disturb no one. Free easy blowing. No resistance in all registers . No one hears you but yourself. Yes, practice anywhere, anytime."-Humes & Berg