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 (9/16in) to 152 mm (6in), 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: 177mm.