It has a long L-shaped Allen wrench to reach upward behind the TV to tighten two safety screws after the TV with its back brackets has been hung onto the track of the wall-mounted plate.  The horizontal part of the wrench won't clear the wall, so it can be turned only a half-turn before being repositioned on the screw, which is extremely hard to find behind the TV where you can't see.  I finally sawed off all but 3/4 inch of the horizontal part of the wrench so that it would clear the wall and I could turn it continuously without repositioning.  That worked well.