A tuner's dream with quick string changes and precise fine-tuning.
The Grover Roto-Grip Locking Super Rotomatics 509 series tuning machines provide an innovative design for quick string changes and precise tuning. You'll love how the thumbscrew mechanism securely locks strings into place, allowing for rapid string installation and removal. The 3-step button adds visual flair while the lubricated 18:1 gear ratio delivers smooth, accurate tuning with minimal backlash. With a 25/64" post hole and durable components, these machine heads are built to handle even the heaviest string gauges. Designed as a drop-in replacement for a variety of popular tuner models, the 509 series tuning machines bring enhanced functionality to your instrument.