ER32 Metric & Inch Collet Rack 2-20mm Organizer Set Holder Stand CNC Tray
That is what this set is designed for. ER COLLET SYSTEM. 11 11.5 mm (0.453 in.). 18 mm (0.709 in.). 16 17 mm (0.669 in.). 27 mm (1.063 in.). 20 21 mm (0.827 in.). 31 mm (1.220 in.).