【AUTOMATIC CENTER PUNCH】: The automatic center punch provides an automatic, high-impact, spring-loaded strike on the cap; Its brass body has a deep, knurled surface for non-slip control. The protective aluminum case can provide convenient storage and transportation. 【DUAL CUTTING BLADES & THREE-SIDED SHANK】: Dual cutting blades and X-type opening design ensure faster and smoother cutting; The 3-sided shank design can prevent the drill chuck from slipping; With the slightest pressure, the sets can cut through wood, sheet metal, steel and other surfaces. 【COATING AND TITANIUM】: High speed steel makes the step drill bit set more durable, titanium coating makes it easy to cut steel sheet, aluminum sheet, copper, plastic and wood and many other types of sheet metal. 【TIME SAVING】: Covering assorted step sizes allows you to drill or enlarge different holes in one bit without constantly changing bits. The size is laser etched into the metal, so it can be drilled accurately and will not wear