Description: These spring collets are made of high quality 65Mn spring steel for CNC milling lathe tool and work-holding engraving machine. There are 3 collets of various sizes in 4mm, 1/8" and 6mm. Collet must be placed into collet chuck nut before inserting into collet chuck. Features: Made from high quality 65Mn spring steel, they are stable in performance. Fine workmanship, good elasticity, high accuracy and run-out tolerance is less than 0.008mm. Collet must be placed into collet chuck nut before inserting into collet chuck. Each collet is marked clearly so you can easily distinguish them. Great collet for CNC milling lathe tool and work-holding engraving machine. Specifications: Material: 65Mn spring steel Model: ER11 Range: 4mm, 1/8", 6mm Height: 17mm OD: 8mm Run-Out Tolerance: <0.008mm Package Includes: 3 x Collets