Jacobs 0061215 CAT V 40 Hold In One Tool Holder with 0 to 13mm Capacity Wide range of capacity. Increased productivity by elimination of collet search or the purchase of multiple collets. Prebalanced at 8000 RPM Bi-directional operation. Can be operated in both clockwise and counterclockwise rotation after firmly tightened. One piece integrated design providing superior durability, balance and ensuring chuck won't fall out during operation High Precision: highly precise, accurate concentricity T.I.R &lt;= .0016-Inch (.05mm) Unique hook locking design with hook wrench, avoids use of hex wrench, which can be worn and create slippage