Lyndex line of high-quality ER standard collet offers High Tensile Chromium Molybdenum Alloy provides greater hardness and less material deformation compared to traditional spring steel collets. Tolerance - Guaranteed to be within 0.0001-inches or better run out at the collet nose. Accuracy- Less than 0.0004-inches at 4 by diameter. Inspection - 100 percent collet inspection, checked 3 times for concentricity. 5/8-inches opening size. 0.625-inches - 0.594-inches collapse range. 41.2-millimeters top diameter. 31.2-millimeters bottom diameter.