This tool is made to attach a ratchet wrench to the handle of an other ratchet wrench, pipe wrench, pry bar, or cheater tube, etc.  Attaching a ratchet wrench adds more leverage in a complete circul ware ever you need to put it. This is so you have the exstra leverage you need to loosen nuts ,bolts or pry something open. The reson the tool is called one directional is because it works better when the tool is leading in the direction that you need to go. The tool will lock on to what ever you put through it. Comes in three sizes. The first tool fits up to 1.0 inch inside and attachs to a 3/8 ratchet wrench and cost $25.00 dollars, The second size tool fits up to 2.0 inchs inside and attachs to a 1/2 ratchet wrench and cost $ 35.00 dollars, or  the biggest one is 2.5 inchs inside of the tool and attachs to a 1.0 inch ratchets wrench and cost $45.00 dollars.  Specify your need.