With the STEELMAN PRO 79993 1/2-Inch Drive, 3/8-Inch Pinless Swivel Impact Extension, 18-inch you’ll be able to access hard-to-reach spaces where maximum power is needed. Made from premium quality, heat-treated 4140 chromoly steel with black oxide finish this extension is designed to hold up to long use. Compared to a universal joint design, the pinless joint design found on this adapter transfers more useable torque to fasteners while adding safety by preventing projectiles common to other designs in the event of accidental breakage. The swiveling head provides a high degree of flexibility, allowing for a wide range of applications.