Features 1、Made of high grade specially formulated spring steel 2、Hardened and accuracy ground 3、Built in self-release design and tools will never get stuck in holder 4、Big clamping force and wide clamping range, widely used in machining centers, general 5、This ER16 collet set is for CNC milling lathe tool and work-holding engraving machine. Specification Features: Made of high grade specially formulated spring steel. Hardened and precision ground. Built in self-release design and tools will never get stuck in holder. Big clamping force and wide clamping range, widely used in machining centers,general milling machines, CNC milling machine, engraving machine, high-speed machines, and other processing. Package Included: 10 x Spring Collet Package List