For standard guitars, set of 6. From the makers of the world’s finest machine heads, come the superb Grover -Roto-Grip’ tuners, which now both lock and fine tune! With this new system, changing strings has never been easier – just thread the string through the tuner post hole, pull it tight, and turn the thumbwheel clockwise. An internal pin locks the string, and you’re ready to tune. Additionally, when replacing strings, Grover’s unique design prevents the thumb wheel from falling out, so you won’t lose it!With an 18:1 gear ratio, precise tuning occurs in seconds – just a few turns of the tuner button and you are -locked’ in tune.Grover ROTO-GRIPS are available in standard and mini formats, and in the usual layout configurations.