Cobalt M42 drill bit – provides upgraded M42 Cobalt jobber-length bits designed for durability, high heat resistance and Hardened surface for stainless steel, cast iron, titanium, light-gauge metal and aluminum Enhanced M42 alloy material – contains 8% Cobalt alloy that delivers 10x life vs. Standard bits High-heat resistant bits – withstand high-temperature applications for extended periods of time Thick web-helix design – provides additional stability in tough applications Surface-hardened tip – penetrates tough abrasive materials Includes – 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 1/2"