Details ✔Sturdy and Quality: The item is mainly made of high-quality A3 steel, alloy, and 4241 high-speed steel with a sandblast treatment, making it high-hardness and resistant to wear, impact, and rust, which can withstand heavy-duty use. ✔Thoughtful Design: It adopts a three-blade design of the middle blade, inner blade, and outer blade, which has a better chip removal effect and makes your drilling efficiency higher. ✔Shank: Its diameter of 10mm(±0.2~1mm) makes it suitable for various kinds of electric hand drills and bench drills for convenient installation and use. ✔Spring-type Guide Drill: This design can eject the chips to make the cutting clean and smooth, which not only saves cleaning time but also shortens the cutting time.  Application It can be used for iron sheets, electric cabinet boxes, weak-electricity projects, sewer pipes, aluminum alloy, pig copper, etc. It applies to bench drill, electric hand drill, electric hammer drill(non-impact), impact drill rotary gear, etc.  Specification Color: Silver Material: A3 Steel, Alloy, 4241 High-speed Steel Surface Treatment: Sandblast Hardness: 89.5-90.5HRC Working Depth: <5mm/0.197in Number of Pieces: 13 Bit Diameter: 16~53mm/0.63~2.08in (16mm/0.63in, 18mm/0.71in, 20mm/0.79in, 22mm/0.87in, 25mm/0.98in, 26mm/1.02in, 28mm/1.1in, 30mm/1.18in, 35mm/1.38in, 40mm/1.57in, 45mm/1.77in, 50mm/1.97in, 53mm/2.08in) Package Size: 27*22*6cm/10.63*8.66*2.36inch Gross Weight: 1.25kg/2.76 lbs Net Weight: 1.14kg/2.51 lbs  Package Included 13* Different Size Hole Saws  Notes 1.Please note that this product does not include an electric drill, bench drill, etc. 2.Please check the integrity of the hole saw before use. 3.When drilling holes, please keep the hole drill perpendicular to the work piece. Please use a small feed force when starting to drill, and use a medium feed force after positioning. When drilling continuously, please use cutting fluid(not included) to cool the cutting edge.