Sale is set of 3 drivers . Guitar Nutdrivers For control pots, output jacks and tuning machine bushings. No more fumbling through your socket set for the right wrench! These sturdy steel deep-socket hex drivers are the right size for common guitar repair jobs. The large comfortable T-handles give you plenty of grip. 6-1/2" (165.10mm) long. #5890 is 10mm, to fit Schaller, Gotoh or Grover tuning machine bushings. #5891 is 7/16", to fit many control pots. #5892 is 1/2", for control pots, output jacks, and rotary switches.