Schaller S-Locks RU, Security Locks, Set consisting of belt pin, lock & lock wheel (one pair each), Silent function for noiseless operation, One-piece belt button made of hardened steel with self-tapping wood thread includes felt disks for the protection of the instrument paint, Extended thread also holds very thick guitar straps to 6 mm, Bolts made of stainless steel for minimum wear and thus highest safety, New design of the ball for best feel, Lock-Wheel with special patent thread and locking screw prevents the locks on the belt loosen, Fully compatible with all existing Schaller Security Locks (without Silent Feature), Surface: Ruthenium