6pc Mini HSS Rotary Tool Saw Disc Wheel Blade With Cobalt High quality As it is with cobalt, it is harder than the normal.This unique great tool set is ideal for precision cuts in wood, Steel, aluminum, brass, copper and more!High speed steel blade and mandrel set is ideal for fine precision cuts in aluminum, brass, copper, wood and plasticMaximum RPM: 20,0001/8" shank screw mandrelHighly durable, sure to last fo