[nova1313]

I built one from a 4 dollar piece of sheet metal I got from Home Depot. I used a drill, and some tin snips. Mind you it's not the prettiest thing in the world but it does indeed work and the temperatures are lowered. I used the stuff they wrap pipes in for the lip edge on the top.

They probably made one took measurements and hand make the rest. It did take me 2 hours to do but thats because there are no dimensions anywhere online and I had to install, cut some, reinstall, cut more... till it sat perfectly.