Yep, gives ~1" of ground clearance on EXT models, but doesn't do much of anything on SWB models, except get rusty from your wheels throwing rocks into it...
Now, if you're doing rock sliders, there is a little over 1" that the plastic rocker covers go down at the front and the rear (the metal rocker is flat the whole way)... So, for the most ground clearance on your rock sliders, the thing to do is cut the bottom of the covers off, front and back... Can't see it standing next to the vehicle, but allows you to get your rock sliders up another 1" off the ground...
You can sort of see mine here:
Mike