This ratchet box wrench will replace two complete sets of box wrenches in the most common metric and inch sizes box wrench has a ratchet function with fine teeth 72 teeth material high quality carbon and chrome molybdenum steel fits on following screw heads square hexagonal double hex and interior wedged metric sizes 8 10 11 13 14 16 17 19 mm imperial sizes 516 38 716 12 816 58 1116 34