"A right handed set of Locking Ratio Calibrated Machine Heads for electric guitar that use 6 in-line tuners with staggered posts (eliminates the need for a string tree). It has a two pin casing that can be used as is, or with our Patented InvisoMatch Mounting Plates. 4 different 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. You can buy Installation Plates in other colors separately. Ratio - Tuned Machine Heads incorporate different string gauges into the tuning equation. From Low E to High E 39:1, 24:1, 20:1, 35:1, 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."