N1 Blade / B10 Blade Most suitable for aluminum, plastic and steel. N2 Blade / B20 Blade Suitable for brass and cast iron. (Right / Left hand users.) N3 Blade / B30 Blade Drilled into tubing or sheet metal. Maximum thickness 4.5mm. N10 Blade / B10 Cobalt Most suitable for stainless steel, copper & aluminum. N10P Blade / E100 Cobalt Blade. Most suitable for steel, copper, PVC & aluminum. N80 Blade Cut along full circumference of each face.