24 Sizes in 3 Individual Drill Bits: This set includes three standard step drill bits that replace 28 individual drill bits, one 4-12mm step drill bit, one 4-20mm step drill bit, and one 3-12mm step drill bit. step bit. Strong Durability: Durable HSS + Titanium. Avoid the inconvenience of a three-flat shank to ensure a firm grip. Easy Drilling: The two-flute design allows for a tighter and smoother cut. Comes with a small pressure and the sets can cut through wood, sheet metal, steel and other surfaces.Extensive Uses: Mark hole locations and start drilling and screwdriving, avoiding the punch. Heat-treated alloy steel, with sharp precision tip, corrosion-resistant brass body with non-slip knurled handle. Self-Centering Punch: Provides an automatic, high-impact, spring-loaded strike when pressed against the , the adjustable cap regulates the striking force. This compact set replaces 24 individual drill bits in Step drills 3pc, including one 4-12mm, one 4-20mm and one 3-12mm. The