●【Multiple Size Sets】: Step drill bit includes 3 standard sizes (10 steps)-3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm,(9steps)-4mm,6mm,8mm,10mm,12mm,14mm,16mm,18mm,20mm,(5steps)-4mm,6mm,8mm,10mm,12mm. ●【Dual Groove Design】: Step drill bit grooves provide a smoother cut that removes burr chips, dust and chips for faster chip evacuation, while helping to prevent chips from flying, allowing for smoother drilling without heating. ●【Scientific Design】: The 118° split point tip step drill bit effectively increases the cutting speed when facing various materials, and can prevent the step bit from deviating from the center line. Design of 1/4" Hexagonal Shank step drill bit can be easily installed on power tools and eliminates falling off hazard. ●【HSS And Titanium Coating】: Step drill bit made of industrial high-speed steel have excellent durability and high-speed punch. Titanium coating improves the step drill bit sharpness and reduces the heat generated by friction to easily cut metal sheets. ●【Compatibility】: Step drill bit easily solves a variety of home repairs and light jobs, it can quickly weigh on bits such as thickness up to 0.2 inches of stainless steel and iron, plastic, wood, fiberglass other sheet metal.