The Chuck Keyless 13Mm 1/2" X 20 Unf Plastic Is A Keyless Chuck Designed For Use With Power Tools, Such As Drills Or Drivers. It Has A 13Mm Diameter Capacity, Which Means It Can Hold Drill Bits Or Accessories With A Shank Size Of Up To 13Mm. The 1/2" X 20 Unf Thread Is A Standard Size For Many Drills, Ensuring Compatibility With Most Tools That Require This Thread Type. The Keyless Feature Allows For Easy Tightening And Loosening Of Bits Without The Need For A Separate Key, Making It Quick And Convenient To Switch Between Different Accessories. The Plastic Construction Keeps The Chuck Lightweight While Maintaining Durability For Everyday Use.