Graph Tech PRL-8731-C0 Ratio Electric Locking Machine Heads with Classic Button - 6-in-Line, locking machine heads for electric guitar, left-hand set, closed construction, each machine head has its own gear ratio, calibrated for the respective string, half turn of any key is a semi-tone pitch change for each string, faster and more accurate tuning of each string, thumb wheel screw on the back to lock the strings, ratio: E - 12:1, B - 20:1, G - 35:1, D - 20:1, A - 24:1, E - 39:1, 6 pieces: 6-in-Line, treble side (right), 2-pin mounting, axis diameter without mounting sleeve: 5.9 mm (0.232""), mounting diameter with mounting sleeve: 9.9 mm (0.390""), incl. 4 sets of InvisoMatch standard mounting plates for use of existing screw holes, weight ca. 37.75 g / 0.083 lbs (single), Classic button, chrome finish