Extreme Durability: Cobalt high speed steel drill bits and titanium coating ensure extreme durability, will stay new and shiny for years. Smooth Drilling: Non-stepping drill tip provides fast and smooth speed. Drill on steel sheet, aluminum sheet, wood board, plastic board, etc. (the thickness of the board should be less than the height of the step drill bits). Use a center punch to mark the spot: Please mark the at the place where you need to drill for easier drilling and improved drill bit life. Keep Your Step Drill Bits Well Organized: All drill bits come in a well-organized case for easy carrying and storage.