Grover Sta-Tite 18:1 ratio horizontal/slotted peghead 3+3 tuning keys in nickel finish. The classic open-gear, butter bean button, and fine 18:1 ratio makes this a favorite for both slotted peghead acoustic and retro electric guitars. Includes mounting screws. Requires 1/4"(6.35mm) holes for the tuning post. Mounting holes on each tuner are spaced 1"(25.4mm) apart. Features Grover's lifetime guarantee.