The Faithfull 16 Piece Professional Holesaw Set contains the 12 most frequently used holesaw sizes, along with two arbors, an extension and an adaptor. These high speed steel bi-metal saws have specially hardened variable pitch teeth for fast smooth cutting. Bi-metal saws offer increased safety as they will not shatter under load. These holesaws are used by construction workers, builders, plumbers and electricians to cut perfect holes in a wide variety of materials including wood, chipboard, plywood, non laminated plastics, plasterboard and non ferrous metals. Suitable for use in most variable speed power drills. Supplied in a sturdy case for safe and secure storage. Contains 12 x Varipitch Holesaws 16, 20, 22, 25, 32, 35, 38, 44, 51, 64, 70, and 76mm. 1 x 3/8in Arbor (14-30mm). 1 x 7/16in Arbor (32-152mm). 1 x Arbor Adaptor. 1 x 300mm Extension Bar. 1 x Aluminium Case.