ER Collet Ultra High Precision 0.005mm / 5u run-out.
Available in ER11, ER16 and ER20 in common sizes 3.175mm (1/8"), 4mm, 6mm, 6.35mm (1/4"), 8mm, 10mm and 12.7mm (appropriate to ER size). Clamping range is that of nominal inner diameter size -1mm (eg. 6mm would accept 5mm to 6mm).
A high precision collet allows for quieter machining, longer tool life and greater cut accuracy.
Also available in High Precision 0.008mm / 8u