I also have one like in the above photo but it's a Currie. Works good but as stated, you need a seat to babysit it. I had the Smittybuilt deflaters but were way too heavy to screw on & drive to the trails. It even states so in the paper work.
If I were in the market I'd get the style Clarke posted. It does everything you need them to do. You can pre set the psi you want, screw them on, drive to the trail & not have to monitor them.