This is why.... you bought a HUMMER

[HumminNBoatin']

Those tubes are like rock rails for the top of the truck. I guess you could call them "tree rails" I know the owner of this truck he is a good guy. Really the way he mounted it all is pretty rudementry but it works. I do not remember exactly what they are made of. But it just has flanges that are literally lag bolted into the body of the truck.

The rack is just a standard aluminum roof rack that he bought from the dealer years ago.