3/8" square drive impact wrenches are used to tighten and untighten bolts. This is a small sized impact wrench which is designed for lighter duty work. Our 3/8” impact drivers are cordless, which improves overall convenience. When choosing an impact wrench the size of the square drive is one of the main considerations, since the larger the size, the bigger the sockets it can support. Impact sockets should be used with impact wrenches.