ER collet is the most widely used clamping system in the world used for a variety of machining applications including boring, milling, reaming, tapping and grinding. The advantages of ER Type Collets are: High polished finish for extra accuracy and long life, especially when clamped in ER chucks Superior clamping strength Fits all brands of ER holders The benefits of ER Type Collets are: Quality: Product consistency and worldwide acceptance Material: Durability and increased collet life Wide Clamping Range: Less collet inventory necessary Broad Product Range: Versatility for a variety of applications Clamping Length: Higher clamping power and improved T. I. R. Matched Tooling System for Best Fit: Compatibility of the whole system results in maximum precision, balance and tool life Precision: Increased tool life and part quality. According the amonut of ordering goods.