The Faithfull Hexagon Keys are six sided wrenches for driving socket screws which are used mostly on machinery for fastening parts tightly together. Fully hardened chrome vanadium. Sizes 15 x Metric 0.7. 0.9, 1.3, 1.5, 2, 2.5, 3, 4, 4.5, 5, 5.5, 6, 7, 8, 10mm. 15 x Imperial 0.028, 0.035, 0.050, 1/16, 5/64, 3/32, 7/64, 1/8, 9/64, 5/32, 3/16, 7/32, 1/4, 5/16, 3/8in.