This Irwin Bi-Metal Holesaw Kit is available in a unique attractive soft storage case incorporating an unbreakable hinge and internal padding to protect its contents. The case has an integral handle, and a cardboard sleeve to contain important product information.The Bi-Metal holesaws cut through a variety of materials, including aluminium, copper, iron, stainless steel, wood, and zinc. They have precision set teeth for faster penetration, and the electron beam weld ensures stronger, longer lasting teeth. The bi-metal construction makes these holesaws tough, and durable. This 17-piece set consists of the following:12 x Holesaws: 16, 19, 22, 25, 29, 32, 35, 38, 44, 51, 65 and 76mm.1 x 9.5mm Mandrel for holesaws 14 to 30mm.1 x 13mm Mandrel for holesaws 32 to 210mm.3 x Pilot Drills.