Other fixings engineering tools screw extractors bolt grips set of 7 power grip screw extractors have reverse spiral flutes for maximum gripping power universal shape fits metric and fractional sizes features a 14in hexagon shank suitable for use with power drills and nut drivers made from durable high carbon steel for longer life sizes 316in 14in 8mm 516in 38in 10mm 11mm 716in and 12in drive size 14in