1、DEEP HOLE PROCESSING: Internal cooling extension rod can bring the milling cutter into the deep hole slot for processing, improves the working efficiency. 2、HIGH HARDNESS: CNC milling extension rod is forged from excellent carbide, quenched and hardened, with high hardness, difficult to deform. 3、FINE GROUND: The inner hole of the extension rod is finely ground, with high concentricity, smoothly thread, high rigidity, strong clamping force. 4、PRECISE SIZE: The milling extension rod is exquisitely manufactured, with precise size, easy to install and removal. 5、MULTI PURPOSE: The extension rod can be widely used in CNC lathes, machining centers, tapping machines, drilling machines, milling machines and other equipment.