2 in reverse order staggered, grooved main cutting edges and spurs 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 fi xed on the shanks of FAMAG auger bit shanks 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.