These bits withstand high temperature drilling applications for extended periods of time. They're desined for heavy-duty drilling through hardened stainless steels, cast iron, and titanium. Sizes Included(2)1/16", (2) 5/64", (2) 3/32", (2) 7/64", (2) 1/8", 9/64", 5/32", 11/64", 3/16", 7/32", 1/4", 5/16", 3/8", 7/16", 1/2"FeaturesIntegrated cobalt for maximum protection and durabilityFully ground for superior quality