Sharpness and titanium coating ensure easy cutting of most sheet metal, aluminum, wood, plastic and some other materials. Non-travel drill bits provide fast and smooth drilling of plates on steel, aluminum, wood, plastic, etc. (the thickness of the plate must be less than the height of the step drill). Cobalt high speed steel and titanium coating ensure extreme durability that will stay new and shiny for years to come. Double edge design and 3-sided shank design. The 3-flute shank design prevents the drill from slipping; the 2-flute design provides a faster, smoother cut with easy-to-read rings, 1.5 times faster than basic drills. Keep the drill bit clean. Replace 50 individual drill bits with 5 piece step drill bits, saving you a lot of hassle and space. Dual flute design provides faster, smoother cuts. Cobalt steel and titanium coatings ensure that the set has excellent durability and will remain sharp for years to come, ideal for cutting holes in steel, aluminum sheets, and more. 1: 3/16" to 1/2" 6 steps (3/16'', 1/4'', 5/16", 3/8'', 7/16'', 1/2' ') 2: 1/8" to 1/2" 13 Steps (1/8" , 5/32", 3/16", 7/32", 1/4", 9/32", 5/16" , 11/32", 3/8", 13/32", 7 /16'', 15/32", 1/2'') 3: 1/4" to 3/4'' 9 steps (1/ 4'', 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4") 4: 1/4" to 1-3/8" 10 Steps (1/4'', 3 /8", 1/2", 5/8", 3/4", 7/8", 1", 1-1/8" , 1-1/4"