Professional tools for commercial or occasional use. Step drills offer a significant advantage over cone drills because they offer a positive stop when a hole reaches a certain size. With a cone drill it is easy for it to dig in and make a hole that is too large. A set of 3 step drills / stepped cone cutters. Cuts a perfectly round hole in sheet metal. SET Includes; Small Drill; 4mm, 6mm, 8mm, 10mm and 12mm. Medium Drill; 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm and 22mm. Large Drill; 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm and 32mm. Ideal for thin metals such as steel aluminium, copper, fiberglass, brass and PVC etc... Fully polishing HSS steel, self starting design. Double flutes make a perfectly round hole and automatically deburr as you drill. Complete in metal tin / case for easy storage and transportation