Multi-function socket tool material: Chrome-molybdenum steel. Portable universal wrench socket set with honeycomb principle design, high endurance and high hardness. Universal Ratchet Socket Set fits standard 7mm(1/4″ )to 19mm (‘3/4″)inch bolt heads . Universal Socket: A universal socket can be adjusted immediately to grasp the hex nut, screw eye, hook, tension screw and bolt head. Works on a power drill . Saving Time Socket Set:The 7mm-19mm socket can be used for general daily maintenance, production lines, mechanical/vehicle repair, household maintenance, manufacturing industry, construction and etc.