<ul><li>12 Pcs ER20 chucks set includes the following collet sizes: 1/16'', 3/32'', 1/8'', 3/16'', 7/32'', 1/4'', 5/16'', 11/32'', 3/8'', 13/32'', 7/16'', 1/2''</li><li>Concentricity: 0.0004"</li><li>Design affords highest gripping power</li><li>True double angle for better accuracy</li><li>For powerful gripping and parallel clamping</li></ul>