Gizmos are really helpful at the Fort. I made my own with Reflectix, clear plastic painters tarp (usually sold as a giant roll in hardware stores), and two cheap tarps (mine were blue). I cut the plastic to the same dimensions as the tarp and then sewed the plastic onto the tarp to make a large pocket. I left one end open so I could slide the Relectix inside. The clear plastic allowed the Reflectix to actually reflect sunlight away from the camper and not just to provide insulation. I made a second one so I would have "gizmos" for both bunks and as they were a little larger than the top of the bunk, they hung over the edges creating additional shade. My portable AC was able to keep my PUP a comfortable temperature during our stay and the "gizmos", which greatly helped, fit nicely flat on the mattresses when I folded up the PUP to go home. One nice thing is that the tarps have eyelets so I can tie down my "gizmos" and I also used heavy duty document clips to help hold them in place on top of the bunks. One other advantage is that I can use them for tent camping as well.