Original Grover Rotomatics 18:1 ratio for finer tuning and greater stability, sold as a set of 6. Includes washers, wood screws and bushings. The housing provides a maximum bearing for worm, gear and string post. Worm and gear are precision cut for perfect meshing. This eliminates backlash and slippage. Gear box has a special lubricant for lifetime, trouble free service. With precision engineering, enjoy exceptional tuning accuracy and stability, freeing you from constant re-tuning.