Grover 509 Series Roto-Grip Locking Rotomatics - Chrome

The 509 Series utilize the famous Rotomatic® design with a "thumb screw" mechanism which locks the string into place, allowing for quick string changes. To operate, insert the string through the post hole, wrap around once, then lock by tightening with the thumb screw. The 3-step button gives these machine heads a distinctive look and sets them apart from other Rotomatics®.