High Precision ER 11 Spring Collets for Collet Chuck/Holder. T.I.R. 0.0003″ – 0.0004″ Clamping range is 0.020″ – 0.039″ Made out of High Quality steel and 100% inspection quality control in the USA.. Best ER Spring Collets in the Industry..HIGHEST ACCURACY: Collet Accuracy: 0.0003″-0.0004″ T.I.R.WIDE CLAMPING RANGE: Clamping Range 0.02″-0.039″ Depending on Diameter.PRECISION CLAMPING FORCE: Provides Maximum Clamping force with Precision Collapsability.HIGH QUALITY STEEL: Made of High Quality Case Hardened Steel for long lasting operating life and elasticity of Collet.QUALITY CONTROL PROCESS: Hand Inspected and Run out Tested 100% Customer Satisfaction Guarantee.High Quality SteelManufacturer100% Guarantee to be Free from any Manufacturing Defects. 100% Customer Satisfaction Guarantee