Patented piano fallboard lock with self-contained locking device. Virtually unbreakable, made of high density, high-performance plastic. Ruggedly built, virtually indestructible. Comes complete with built-in Masterlock and 2 keys. Clamp opening is 6-1/4" to fit virtually all acoustic pianos. Includes 2 pre-drilled shims to allow height adjustment for smaller fallboards. Easy to install. Hands Off Locks can be special ordered with matching locks (keyed alike) at no extra charge - particularly convenient for universities or churches with multiple pianos. Manufactured in the US by Pianotek Supply Company. Please let us know if you have any questions.