Features: - Made by HSS with heat treatment and Titanium Nitride coating. - Engraved Sizes to easily identify which size you need with the contrasted, laser engraved sizes inside the step drill bit flute. - Increase the hardness and makes the bits last up to 4-5 times longer than ordinary drill bits. - Drill round holes in most metals, plastic, wood, etc. - Self—starting tips will not skid, no need for center punching or pilot drill. - Designed to auto deburr the hole cut - Used on electric drills and drill presses. - Triangular shank will not spin inside the chuck.