GTS 01-116 CryoCobalt (8mm) 5/16" Drill Bit 3 PackHarder Metal Drill Bits Drill Harder Metals Added cobalt increases the microsharpness and allow the bits to drill metals up to 58Rc including hardened, high strengthe alloy steels Long Life Cryophase tratment improves drill bit flexibility and extends bit life Thicker Web Design provides extra strength neede for tough materials and reduces breakage GM and I Car Approved Contains 3 5 16" CryoCobalt Drill Bits