Honestly I wouldn't want to build another one. It took me two months to build mine partly because I am lazy but also because work has been wearing me out. Besides, part of fabbing one up is that it will be unique and you can build it anyway you like. It is basically a box with lights on it. I used electrical conduit but it can be made out of almost anything. I got a lot of my inspiration from a few of the videos on youtube. Heck, one guy used the same conduit I did and used fittings instead of bends. You are only limited by your imagination.
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Roof rack build for single cab