This ER collet is used for CNC milling lathe tool and workholding engraving machine.<br />Collet must be placed into collet chuck nut before inserting into collet chuck.<br /> <br /><b>Specifications:</b><br />Model: ER20<br />Clamping Diameter: 1/4-inch<br />Material: 40Cr Steel<br />Precision: 0.015mm / 0.0006-inch<br />Total Height: 31.5mm / 1.24-inch<br />Outer Diameter(Max): 21mm / 0.83-inch<br /> <br /><b>Package Includes: </b><br />1 x Spring Collet<br />