These are standard ER16 collets for holding endmills, cutters, routers and drills in your CNC, router or milling machine. They can also be used as a workpiece holder in a lathe. With a run-out tolerance of 0.015mm (0.0006"). Individually packaged in a robust box. Choose from the following individual sizes or a Set of 10 (1 of each size): 1mm - clamping diameter: 0.5-1mm 2mm - clamping diameter: 1.5-2mm 3mm - clamping diameter: 2.5-3mm 4mm - clamping diameter: 3-4mm 5mm - clamping diameter: 4-5mm 6mm - clamping diameter: 5-6mm 7mm - clamping diameter: 6-7mm 8mm - clamping diameter: 7-8mm 9mm - clamping diameter: 8-9mm 10mm - clamping diameter: 9-10mm Suitable accessories available are the ER16 Clamping Nut, and ER16 Wrench