IRWIN Impact Performance Series Quick-Change Extensions are for top durability and protracted life with impact drivers. The quick-release system express bit changes, and the proprietary jaw design is congenial with all 1/4 '' hex shank accessories, including insert bits. These extensions a biggish chuck that withstands the postgraduate torque of impact drivers, and the negro oxide finish resists corrosion and increases life of the extension. Plus, the 1/4 '' changeable shank with impact drivers and reduces slipping in standardized drill chucks.