Item Type: Collet Chuck Material: Carbon steel Model: ER40 Size: Outer Diameter: Approx.100mm/3.9in Height: Approx.42mm/1.7in Accuracy: 0.005 Quenching Hardness: 45-50HRC Package List 1 x Collet Chuck 1Function: This collet can be mounted to the backing plate of your choice for use on a lathe or as a fixture on a milling machine 2High Hardness: The collet chuck is made of carbon steel, with the quenching hardness of 4550HRC, has strong oxidation resistance and high hardness 3Easy Installation: This collet is standard and compact in size, light in weight, more convenience to the installation 4High Accuracy: This lathe collet chuck has high accuracy up to 0.005 ensures high working efficiency 5Wide Application: The collet chuck is suitable for CNC milling machine, turning tool, engraving machine etc.