Features 1、Made of high grade specially formulated spring steel. 2、It was hardened and accurate ground makes it applicable to high accuracy process. 3、 High accuracy and large chuck force,high tensile strength. 4、100% brand new, high-quality and has long service life. 5、Made of high grade specially formulated spring steel. Specification Features: Made of high grade specially formulated spring steel. It was hardened and accurate ground makes it applicable to high accuracy process. Built in self-release design and tools will never get stuck in holder. High accuracy and large chuck force,high tensile strength. 100% brand new, high-quality and has long service life. Specification: Type: 1mm 2mm 3mm 4mm 5mm 6mm 7mm Material: 65Mn Spring Steel Accuracy: 0.008mm Concentricity: 0.008mm Package List: 7*CNC Collet Package List