The simplest, easiest strap lock. Nothing to install. These stretchy rubber discs keep any strap from slipping off. They're like the cap gaskets found on Grolsch™ beer bottles, but ideally sized for strap buttons. Put your strap on, then add a Stopper over each button. Your strap stays put! "I prefer to keep my guitars original, even changing the strap button bugs me. Strap Stoppers are a reliable way to secure the guitar, keep everything original, and not scratch the finish in the process." —Erick Coleman, guitar repairman and StewMac tech advisor Specifications: Outer diameter: 1" (25.4mm) Inner diameter: 0.300" (7.62mm) Thickness: 0.090" (2.29mm) This is a package of 4 Grolsch-style red Strap Stoppers for securing 2 guitars.