Nickel plated vintage style individual open geared guitar tuners with butterbean buttons, brass gears and 18:1 ratio for smoother, more precise tuning. Set of 6 individual tuners, 3 per side. Grover's newest and best replacement for Martin and other instruments from the 1930's to '60's which had the original nickel Sta-tites. Shaft length - 1", shaft diameter - 1/4", distance between screw holes - 1" (approximate).