Jacobs Chuck 0064004 VDI 30 Hold In One Tool Holder with 0 to 8mm Capacity Wide range of capacity, Increased productivity by elimination of collet search or the purchase of multiple collets Bi-directional operation; Can be operated in both clockwise and counter clockwise 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 (.05-mm) Unique hook locking design with hook wrench, avoids use of hex wrench, which can be worn and create slippage