These Sockets have a built-in Swivel Joint for Impact applications. The Swivel is a simple coupling device that allows the thing fastened to turn around freely upon it. It is a flexible Socket particularly useful for tightening nuts located at different angular positions. These are available in 3/8" & ½" square drives from 7 mm to 24 mm across flat & equivalent SAE sizes. The Swivel Sockets with built-in extension are also available to cover & reach upto 200 mm.