The Irwin Multi Material Circular Saw Blades have construction grade tungsten carbide tips which retain their edge for longer and can be re-sharpened. They have expansion slots which dissipate heat to prevent warping and the plate is fully hardened. The blades have Triple Chip Grind teeth (TCG) for excellent finish of the cut. They have a corrosion resistant coating for longer quality performance. The IRWIN IRW1897442 Multi Material Circular Saw Blade has the following specifications:Diameter: 216mm.Bore: 30mm.Reduction Ring: No.Teeth: 84.