Roto-Grip Locking Rotomatics utilizes the famous 18:1 Rotomatics design with a “thumb screw” mechanism which locks the string into place. Insert the string through the post hole, wrap around once, then lock by tightening with the thumbscrew. Perfect replacement for the most standard machine heads. Includes all mounting hardware. Allparts #TK-7935. Twin Town Guitars does guitar repairs on instruments, electronics, and do Plek work! • MFSKU TK-7935-001 • UPC 645208048586