Flex or allows bits to flex up to 15 degree which equals increased durability and reduced breakage for longer bit life. This set allows you to maximize you impact ready system. It features a 10X magnetic screw lock system for strong fastener retention and is preferred by professionals everywhere. The bits are placed directly in the impact driver no run out and allows for access areas. It also minimizes drops and reduces wobbling. This set features a full range of sizes, from 2 inch to 6 inch screw driving bits and are removable to be used across a full bit set. These bits are durable and jobsite tough.