The Graph Tech 5-string Ratio 4+1 bass Classic Clover Leaf button tuning machine heads incorporate different string gauges into the tuning equation. Graph Tech 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 adjustments, delivering predictable, precise tuning on every string. The Graph Tech PRB-5411 is a right-handed set of Ratio calibrated machine heads for bass guitars that use 4 x 1 configuration.