Comments: I ordered a set of 4 of these from Poly Performance. The ones I have are for a TJ and a few ZJ models if I remember correctly.
They will work on the front or the back. There is no size difference in front or rear spacers, so don't be alarmed if you get a set and all of them are the same. I have these on the back and 1'' Pro Comp spacers in the front.
Front install is not a problem, but I had a time with the back. It was a tight fit on my Jeep.