Grover 150 Series Imperial 3+3 tuning keys in gold finish. This is the original premium quality full size sealed machine head - perfect for jazz boxes and other arch top electrics. 16:1 gear ratio. Metal art deco style stepped button. The 150 Series features a shorter top screw tab on the housing, for easier fit on smaller headstocks and to prevent backplate overlap with closer peghead hole spacings. Includes press-in bushings and mounting screws. Requires 25/64"(10mm) peghead holes. Features Grover's lifetime guarantee.