I've got one on my truck, and it works as advertiesed. It helps a bunch with my semi-grabby clutch. It's a box about the size of a computer mouse, and it has four hose barbs for the vacuum lines and a couple of wires (electrically switched). The suggested mounting place is on one of the bolts on the intake horn at the heater grid. Pretty much plugs right in. The hard part was running the wiring into the cab (which isn't hard). I didn't use their switch, which was a bit too ugly for me. I ended up using a button-type rocker with a lighted "on" position, and mounted it down in the plastic by the xfer case shifter. Tapped into the key-on power lead by the steering column. Quick, easy, works.
I'd get you a picture, but that part of my engine isn't currently in place!