Features: Made of premium high speed steel, sturdy and durable The blade is extremely sharped, with good perforation capability. Taking the form of a short open cylinder with saw-teeth on the open edge, perfect for installing locks, knobs in doors and cabinets Can be used to make holes in wood, thin steel sheet, aluminum alloy and other soft metal sheet. Suitable for hand held electric drill, stand motor-driven drilling machine and mobile ribbon type magnetism drilling machine. Specification: Material: High Speed Steel Size:15/16/18/20/22/25/26/28/30/35/40/50mm Hole diameter:15mm/0.6in,16mm/0.6in, 18mm/0.7in, 20mm/0.8in, 22mm/0.9in, 25mm/1.0in, 26mm/1.0in,28mm/1.1in, 30mm/1.2in, 35mm/1.4in, 40mm/1.6in, 50mm/2.0in Uses: Opening hole Weight: Approx.919g/32.4oz Package list: 12 x Hole Saw drill bit 1 x hex wrench 1、Made of premium high speed steel, sturdy and durable 2、The blade is extremely sharped, with good perforation capability. 3、Taking the form of a short open cylinder with saw-teeth on the open edge, perfect for installing locks, knobs in doors and cabinets 4、Can be used to make holes in wood, thin steel sheet, aluminum alloy and other soft metal sheet. 5、Suitable for hand held electric drill, stand motor-driven drilling machine and mobile ribbon type magnetism drilling machine.