This drill chuck does not have any knurled surfaces as the Ergon-Grip design has only smooth surfaces. Thus, handling with hygienic gloves is made easier. The smooth Ergon-grip surfaces also reduce the risk for contamination and corrosion. Built for most precise bores without need for a clamping key. Surfaces are electropolished. Edges are round. All parts hardened for a max. chuck life. Ducts and all contact surfaces are ground. Checking for functioning and precision for the complete range is in accordance with standard ISO 10888. Through hole. Permanent markings, stamped. For clock-wise rotation. Also available as flushable version with flushing pin – European patent Nr. 1972287.