8 Pc. Bolt Biter Nut Extractor & Driver Set Bi-directional design for removing or tightening damaged fasteners. Tapered entry easily seats on a damaged fastener. Dual sized sockets designed to work with both SAE and metric fasteners. Torsion zone offers up to 50x longer life in high torque impact applications. Chrome molybdenum alloy steel (Cr-Mo) for exceptional strength and long lasting durability. High-visibility etched markings provide quick size identification. Black oxide finish to resist corrosion. Minus-size sockets fit a wider range of damaged fasteners. Included pivoting GEARCASE insert rails for storage and organization 86170