1、HIGHER HARDNESS AND WEAR RESISTANCE: Drill bits adopt Ti plated high speed steel material, with higher hardness and wear resistance 2、EFFECTIVELY PREVENT FROM SLIPPING: The drill bit adopt a 118° X type opening design, which can effectively prevent from slipping 3、QUICK DRILLING AND SMOOTH CHIP REMOVAL: Double straight grooves provide quick drilling and smooth chip removal, possess high efficiency 4、FAST AND EFFICIENT: Step drill have step size, easy to use. The set support dual purpose of sawing and milling, fast and efficient 5、FOR SLOTTING, REAMING AND PUNCHING: Suitable for slotting, reaming and punching of thin wood, metal and plastic plates, very practical Item Type: HSS Drill Bit Set Material: Ti plated high speed steel Shank Type: Hex shank step drill, round shank saw drill 4mm-12mm Step Drill Bit: Tool Diameter: Approx. 4mm / 0.16in 6mm / 0.24in 8mm / 0.31in 10mm / 0.39in 12mm / 0.47in Total Length: Approx. 65mm / 2.56in Shank Diameter: 6.35mm (1/4in) 4mm-20mm Step Drill Bit: Tool Diameter: Approx. 4mm / 0.16in 6mm / 0.24in 8mm / 0.31in 10mm / 0.39in 12mm / 0.47in 14mm / 0.55in 16mm / 0.63in 18mm / 0.71in 20mm / 0.79in Total Length: Approx. 73mm / 2.87in Shank Diameter: 6.35mm (1/4in) 4mm-32mm Step Drill Bit: Tool Diameter: Approx. 4mm / 0.16in 6mm / 0.24in 8mm / 0.31in 10mm / 0.39in 12mm / 0.47in 14mm / 0.55in 16mm / 0.63in 18mm / 0.71in 20mm / 0.79in 22mm / 0.87in 24mm / 0.94in 28mm / 1.1in 30mm / 1.18in 32mm / 1.26in Total Length: Approx. 101mm / 3.98in Shank Diameter: 6.35mm (1/4in) 3mm Saw Drill: Tool Diameter: Approx. 3mm / 0.12in Total Length: Approx. 60mm / 2.36in Shank Diameter: Approx. 3mm / 0.12in 6mm Saw Drill: Tool Diameter: Approx. 6mm / 0.24in Total Length: Approx. 85mm / 3.35in Shank Diameter: Approx. 6mm / 0.24in 8mm Saw Drill: Tool Diameter: Approx. 8mm / 0.31in Total Length: Approx. 93mm / 3.66in Shank Diameter: Approx. 8mm / 0.31in 1 x 4-12mm Straight Grooved Step Drill Bit 1 x 4-20mm Straight Grooved Step Drill Bit 1 x 4-32mm Straight Grooved Step Drill Bit 1 x 3mm Saw Drill 1 x 6mm Saw Drill 1 x 8mm Saw Drill 1 x Plastic Box