6 piece set of EXTREME Cobalt metal drill bits, delivering superior drilling into metal. Featuring a non-slip shank, a no-walk tip for curved surfaces and a strong central core that improves fracture stability, particularly in freehand use (4.8mm diameter and up). Suitable for portable or stationary drilling of high alloy content steels and metals with a tensile strength up to 1100N/mm?. The ‘no-walk’ tip allows for easier penetration of all surfaces (5mm and above). Cleaner, more accurate, burr-free holes due to recessed cutting wings. No slip shank; spin proof three sided shaft for optimal grip in drill chuck.