This is just a simple CamBuckle adjustment strap for fine tuning your ledge set up.  This features a super heavy weight nylon strap and CamBuckle for you to hang your ledge from allowing you to perfectly fine tune your ledge position no matter the anchor you choose to bivy from. 
Always back up your tie in point and ledge main point with your rope!  Redundancy is key to a proper bivy!