6 Pics 1/4" to 1/8" Collet Chuck Driver Adapter for Lathe CNC Router Cutter Milling Bit For CNC machine tool chuck conversion, conversion size: 6mm to 3.175mm High precision, suitable applicable to different specifications of the bit tool and chuck Material: Spring steel Size: 6.35mm to 3.175mm (1/4"TO1/8") Total length: 22mm