The Faithfull 16 Piece Varipitch Universal Holesaw Kit manufactured from a bi-metal material with hardened teeth made from high speed steel and a variable tooth pitch for fast smooth cutting. They are ideal for use on a wide variety of materials including wood, chipboard, plywoods, plasterboard, non-laminated plastics, and non-ferrous metals. Suitable for use in most variable speed power drills. Supplied in a sturdy aluminium case, 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.