Features: Hole saw is made from carbon steel, durable and practical. The blade is extremely sharped, and resistance to cutting. Have good perforation capability. It removes material from the edge of the hole, cutting out an disc of material. Perfect for installing locks, knobs in doors and cabinets or drilling larger diameter holes through desks etc. This hole saw bit is only suitable for wood, not used in metal There are4 hole saws in different sizes that you can use to open different holes. Specification: Material: Carbon Steel Hole saw diameter: 32mm/1.3in, 38mm/1.5in, 44mm/1.7in, 54mm/2.1in Weight: Approx.209g/7.4oz Package list: 4 x Hole Saw Drill Bit 1 x extension rod1 x hex wrench 1 x nut