The PRL-8731-LG0 is a left handed set of Ratio Calibrated Machine Heads for electric guitar that use 6 in line tuners. It has a classic shaped button, has a two pin casing and is finished in Gold. 4 Sets of InvisoMatch mounting plates in brushed aluminum are included to make installation on most guitars fast and accurate by using your existing screw mounting holes. Ratio - Tuned Machine Heads incorporate different string gauges into the tuning equation. From Low E to High E 39:1, 24:1, 20:1, 39:1, 20:1, 12:1. We balanced the gear ratios to each string simplifying the tuning process. With Ratio, a half turn is a semi-tone! Every string reacts the same to any tuning adjustment. Predictable, precise tuning, on every string.