This FISCH Forstner bit with its βWave Cutterβ edge bores a very clean 20mm hole. The wavy cutting edge virtually eliminates the risk of tear-out, around the edge of the hole. The Wave edge generates considerably less heat and allows cutting speeds to be increased with less effort required to drill the hole. Forged from one piece of high quality tool steel for extra strength the 1/4" hex shank ensures a very secure fit in a chuck or hex shank holder. FISCH Wave Cutter Forstner Bits are forged, before being CNC ground and then hardened meaning; accuracy and sharpness are a premium. Overall length of 80mm with 55mm cutting depth. Optimum cutting speed; 1,800 rpm softwood, 1,000 rpm hardwood. All FISCH bits are made in Austria.-bg