These guitar machines are a triumph in engineering and styling. The housing provides a maximum bearing for worm, gear and string post. Gear ratio is 14:1. Worm and gear are precision-cut for perfect meshing. This eliminates backlash and slippage. Countersunk tension screw permits player to regulate turning tension to any degree. Gear box has a special lubricant for lifetime, trouble-free service. Includes 5/8″ washers, bushings and wood screws.