This 9 piece professional holesaw set is a good general set and contains the six most frequently used plumbers holesaw sizes, along with two arbors and an adaptor These high speed steel bi-metal saws have specially hardened teeth made from high speed steel with an 8% cobalt content for durability Bi-metal holesaws offer increased safety as they will not shatter under load. The variable tooth pitch provides a fast and smooth cutting performance These holesaws are used to cut perfect holes in a wide variety of materials including stainless steel, aluminium, sheet metal, mild metal, non-ferrous metals, cast iron, hard/soft wood, chipboard, plywood, plasterboard and PVC Suitable for use in most variable speed power drills Plumbers holesaw kit containing: 19, 22, 29, 38, 44 and 57mm Holesaws1 x 3/8in Hexagon arbor1 x 7/16in Hexagon arbor1 x Arbor adaptorSturdy case, Weight: 1.33 Pounds, Manufacturer: Faithfull