Three high-speed HSS M2 double flute step drills. Double straight flutes for efficient swarf clearance. Allows clog-free, precision drilling of eighteen different size holes with just three bits. Size 1: 4-12mm. Size 2: 4-22mm in 2mm increments. Size 3: 4-30mm in 2mm increments. Supplied in flip-up metal case. Model No. AK4733