Features Exquisite Workmanship: This chuck tool set adopts vacuum quenching treatment, which can realize carbon and oxygen carburization and improve hardness, and fine grinding can improve corrosion resistance. One Piece Molding: This CNC chuck toolholder holder adopts internal and external cone fine grinding, and the chuck and the inner cone of the machine body are formed in one time, with uniform strength and high concentricity. Firm Structure: The back pull clamping design of this NT30 ER40 Collet Chuck Tool Holder Set and the fastening design of the pull rod screw can effectively prevent the handle from falling off. 40CR Alloy Steel: This chuck tool holder set is made of excellent 40Cr alloy steel material, which has high hardness and wear resistance and is not easily deformed or corroded by long-term use. Wide Application: This CNC chuck tool holder with wrench is widely used in CNC machining centers, engraving machines and other high-speed processing machines, which is efficient and durable. Specification: Item Type: Chuck Tool Holder Model: NT30 ER40 Material: 40Cr Alloy Steel Drawbar Thread: M12 Tail Aperture: Approx. 12mm / 0.5in Structure Type: Integral Accuracy: 0.003 Scope of Application: CNC machining center, engraving machine and other high speed machines Package List: 1 x Chuck Tool Holder 1 x ER40 Wrench Package List 1 x Chuck Tool Holder 1 x ER40 Wrench