Description: Size Includes - Bit #1 (6 Steps): 3/16", 1/4", 5/16", 3/8", 7/16", 1/2"; Bit #2 (9 Steps): 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4"; Bit #3 (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". Replace 28 individual , save s great amount of money and troubles. HSS Titanium Coating classic high speed steel with titanium coating for proven capability and durability in drilling holes in plastic, aluminum, copper, stainless steel and many other types of sheet metal. Meet Your Demands - With the step we offered, you can process different kinds of diameter holes, which greatly saves you a lot of trouble. Great for steel sheets/ aluminum sheets/ copper/ plastic/ wood board and many other types of sheet metal with ease countersunk. Suitable for home diy, and general building/ engineering use. Design - The titanium coated step drill bit set adopts groove design, allows particles escape easily, help the electric drill clamp it more firmly, prevent sliding or falling off during rotation. Wide Application - Prefect for sheets of metal,wood, plastic, aluminum, copper, etc. Specification: Material: HSS 4241 Shank Type: 1/4" hex shank, quick change Size Chart: Bit #1 - 3/16", 1/4", 5/16", 3/8", 7/16", 1/2" Bit #2 - 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4" Bit #3 - 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" Package Includes: 3 Pieces Step