carbon steel: Material: Chromium Vanadium Steel ( has more good wear resistance and toughness than Chromium-molybdenum steel the former is commonly used in Socket the latter used for Screwdriver): 1/2 square drive for use with socket wrench or impact wrench SAE sizes:11/16 3/4 5/6 7/8 1 : The innovative spiral profile digs itself into the head of a damaged screw or nut allowing it to be easily loosened.: The specially hardened sockets with corrosion protection are designed for the removal of damaged bolts screws and nuts.: Application:Great for removing stripped broken head rusted recessed unscrew free-spinning and deck nuts.: fabric_type: carbon steel