I purchased three Ferret Nation 142 cages. One of these was taken apart and one of each of the two sections was placed on top of the other two cages to make two 3 section cages. It was actually cheaper to do this than to purchase two add ons. As an aside, I also took the shelves off of the bottom and put the wheels back on to make them, 1-able to fit through a door, and 2, closer to the ground. I am a chronic procrastinator, so it has been only recently that I called Midwest to try to replace the shelves. I had proof of the purchase of one of the cages, but not the other two. They had me take pictures of the cages and the shelves to make sure that they were indeed replacing "old" shelves and not new ones. I did all of this via email and this was just a few months ago. Hope this helps. If you are interested in how I modified the cages, I will try to help if you want to contact me. I was NOT complicated at all. Cheryl [Posted in FML 6552]