Jacobs Chuck 0080281-03 1-1/4-Inch Milling Chuck Collet with 12mm Diameter RPM: up to 10,000 High torque: unique bearing system provides superior grip Rigidity: High alloy steel properly hardened and heat treated provides greater durability and longer life High Precision/Accuracy: concentricity TIR &lt;= .0002-Inch at 4-Inch from the nose Laboratory certified for accuracy and gripping torque