Tooth configuration optimised for the fast cutting of sheet steel. Cuts sheet steel faster than standard hole saws. 8 teeth per inch for a smoother cutting action. Cleaner holes with no burring. Premium grade 8% Cobalt Alloy Steel construction for an extended working life. Slimline design reduces frictional heat build up and prevents tooth burn out. Compatible with impact drills E6,3 Drive System. Flared shoulders prevent overdrilling ~ avoids damaging inner components of electrical cabinets and junction boxes.