Two in reverse order staggered, grooved main cutting edges and taper taps with longitudinal grooves - both effecting that a clear less feed rate force is necessary. Also they minimize the friction and the growth of heat. With lateral attachment screw for being fixed on the shanks of FAMAG auger bits, To fit on FAMAG auger bits with shank-Ø 13 mm. Drilling and counterboring in one single operation. Recommended for soft wood. Can be used universally on all FAMAG auger bits with shank-Ø 13 mm. Alloyed tool steel 500 - 800 rpm e.g. Ø 40 mm 800 rpm in soft wood.