KATA 20pcs Hole Saw Kit With carbon steel and heat treated,This set is suitable for the most popular size of ordinary wood, thin PVC board and plastic, which is high precision,portable and safety. This hole saw kit including normal 2 inch hole saw,3 inch hole saw,4 inch hole saw,5 inch hole saw and 6 inch hole saw. Diameter: 3/4" (19mm), 7/8" (22mm), 1-1/8" (29mm), 1-1/4" (32mm), 1-1/2" (38mm), 1-3/4" (44mm), 2" (51mm), 2-1/2" (64mm), 3" (76mm), 3-1/2" (89mm), 4" (102mm), 5" (127mm), 6"(152mm) Note: 1. In upgraded version, put the Installation plate between saw blade and nut can be useful to prevent saw blade from being damaged. 2. It's recommend using machines with drill speed less than or equal to 1000 rpm, which can prolong the life of the hole saw. 3. Please wear protective goggles and gloves when using KATA hole saw kit, because it's safe for you. 4. After the use of a few anti-rust oil on the surface of the filter to avoid natural oxidation, can improve its service life. 5. Not suitable for hard material such as metal, density board, aluminum, stone and computer tables. Specification: Material: High Carbon Steel Cutting Depth: 25mm Adapted Machines: Electric drill, Impact drill, Bench drill etc.