3/8" F x 1/4" M Locking U-Joint Adaptor

Socket is made of the finest quality S.A.E. 4140 Chrome Molybdenum high-impact steel • Patented hex ball and socket design eliminates connecting pin for increased safety • Ball and socket distributes force evenly for greater torque and longer life • Eliminates broken connecting pins, the major source of U-joint failures • Drive anvil locks into straight position when flex function is not required • Can be left on impact wrench and engaged only when needed • Patented design combines drive adaptor and universal joint into one handy tool