The IRWIN bi-metal holesaws have been designed for the professional, and made to provide long lasting performance for use in general construction, electrical installation, plumbing, heating and ventilation, and remodelling applications. The sharp, variable tooth (4-6 pitch) design provides a faster cutting action and enhanced performance in a variety of materials and cutting applications. The bi-metal construction and the electron beam welded teeth give the user a stronger, longer lasting blade. The IRWIN holesaw range is available from sizes 14 mm (9/16 Inch) to 152 mm (6 Inch), with a line up of high quality arbors and a pilot drill to cover all application requirements. Cuts a variety of materials including: aluminium, copper, iron, stainless steel, wood and zinc.Irwin Holesaw Bi Metal High Speed Diameter: 25mm.