Hipshot Grip-Lock Open Gear 3+3 Tuner Upgrade Kit Install modern open gear locking tuners without drilling! Give your 3+3 headstock a much-needed makeover with the Hipshot Tuner Upgrade Kit. You can install them on any headstock and tuner spacing, without drilling! Instead of your old, time consuming string change ritual, simply pull the string through the hole and tighten the thumbwheel. A small pin inside the string post will grip your string and lock it in place for worry free tuning! The patented Universal Mount Plate (UMP) included free in this kit means your tuners will retrofit without drilling or screwing. The special tabs in the plate securely hold your tuning machines in place to make install a breeze! Grip-Lock pin and thumb wheel system 18:1 tuning ratio for super fine adjustment Compatible with 13/32" (10mm) pegholes String post hole fits strings up to 0.060" Set of 6 includes mounting screws, threaded bushings, and washers Cast housing Also available for 6-in-line pegheads.