Set of three HSS step drills, sizes #1, #2 and #3 Size #1: 1/8 to 1/2 by 1/32 Increments: 3/16-1/2 by 1/16 Increments, 1/4-3/4 by 1/16 Increments Set comes in plastic case, Step drills you can sharpen yourself (both and flute). lusive single radial concave flute crates perfectly round holes in metal, plastic wood and other thin materials without center punching. Contructed of industrial grade high-speed molybdenum steel, heat-treated and temperature for long life. Slef-stating tip. No center punching needed. Automatically deburrs top side of hole. Ideal for steel, copper, aluminum and other thin meterials