This is an update to a prior post. There were the correct number of panels, not as I had originally posted. As for the pan bottom, indeed it is NOT INCLUDED which seems strange to me, if you are trying to potty train an animal. I totally missed this when ordering, and maybe that is why the price was the best I found online? It did go together easily but as it is large, it was helpful to have someone just hold the panels upright. I don't know how we'll it would hold up for a large dog, but we are using this under recommendation of our vet, to retrain our cat to the letterbox as she has had some problems. We needed to find something TALL and enough to allow three dimensional roaming for her.