Schaller

The
world’s favorite change and lock system for guitar straps. These new
revolutionary S-Locks are silent. They feature one-piece hardened steel
strap buttons, aesthetic design, perfect handling, an elegant Lock-Wheel
and all former hiccups have been tackled! New and unique solid
one-piece strap button in hardened steel with self-tapping wood thread.
Simply screw it on with an Allen key (size 3 mm/ 1/8″). Hardened steel
and more than double thickness of the strap button guarantees maximum
security against breakage. Including high-grade felt washers for
ultimate protection of guitar’s finish