Features 1、Excellent Cutting Ability: Made of heat treated and tempered high carbon steel with Ti coating, which bring excellent cutting ability 2、For Various Materials: Hole saw bit kit can be used for steel, aluminum and other metal, plastic or wood materials 3、For 15 Degree Chamfer: Drill bit hole saw support enlarged or countersunk hole, deburring edge, and 15 degree chamfer 4、16 18.5 20 25 30mm Opening Diameters: There are 5 opening diameters, which is 16 18.5 20 25 30mm, so that will meet your different using needs 5、With Hex Wrench And Spring: Equipped with hex wrench and spring, which is convenient for you to install, disassemble and use Specification Item Type: Metal Hole Saw Bit Material: High carbon steel Surface Treatment: Ti coating Hole Diameter: Approx. 16mm / 0.63in 18.5mm / 0.73in 20mm / 0.79in 25mm / 0.98in 30mm / 1.18in Shank Diameter: Approx. 8mm / 0.31in Uses: Steel, aluminum and other metals, plastics or wood Package List 5 x Metal Hole Saw Bit 5 x Hex Wrench 5 x Spring