It is Precisely sized, Chambered end inserts smoothly into fastener heads, reducing wear.Easy to get wrenches in and out.High visibility sized marked on case for fast selection .Long arm wrenches provide extra reach and greater torque. Allen Keys are made from Chrome Vanadium Steel which withstand up to 30 Percent higher Torque as compared to Allen Keys made from Carbon Steel. Applications: Can be used on 1) Common machine parts 2) Bicycle maintenance 3) Professional Home Appliance Maintenance