Introducing the Astro Tools 78103 (1/4" Drive) and 78303 (3/8" Drive) 3-Piece Locking Hex Shank Impact Adapter Extension Sets. 1/4" hex Impact drivers are getting more powerful and smaller by the year, making them a more popular quick repetitive fastener power tool than ever. What can take that utility to the next level is additional reach, moving your tool away from the work piece with impact rated extensions, and the functional addition of locking socket retention. These two new 1/4" & 3/8" square drive sets feature a simple collar sleeve to pull back and release your socket when you want and keep that socket locked onto the extension when you need it to not come off while performing multiple fastener removals and installs quickly. Built to withstand the demands of high-torque modern impact drivers, these impact adapter extension sets each include 3", 4" and 6" extensions with quick change 1/4" hex shanks.