This is the "Free Hole Saw W-F for Hard Building Materials (K-107)" from Kanzawa Tekko. It is suitable for drilling holes in hard building materials such as exterior walls like ceramic siding, FRP, decking materials, and fire-resistant boards. The blade and center drill are equipped with carbide tips, providing excellent durability. The well-balanced two-blade design allows for efficient cutting. The hole diameter can be adjusted with a butterfly screw without the need for tools, and it supports diameters from 40mm to 200mm.