THE WORST INSTRUCTIONS I HAVE EVER SEEN!  Barely 3 pages, they don't show you how to assemble the locks and it ain't easy to figure out. There are two piece of bracket, one flat and one spacer bracket.  The instructions do not mention either, even the picture in the instructions only shows the spacer bracket connected to another spacer bracket.  As a whole it seems solid. There is nothing to secure it in place, I guess it's weight will keep it from moving, I hope. I don't see how this helps with larger dogs because any of them could jump out of this in one leap especially more athletic ones.