I purchased this hoping that it would help keep down on the tracking of the litter. Which it did while I had it on, but....my larger boy won't use the catgenie with it on :( My 2 girls don't mind it at all and I'm really surprised that my boy won't use it due to prior to the catgenie they always had covered litter boxes. I had the Fresh Step Automatic Litter Box and I had no problems with any of them using them with the cover. But I think he feels clostraphobic in this one or something? He seems to fit fine in it, but for some reason he just don't like it. So I have to keep it off. Therefore I have the top & no use for it. I guess if I ever get a 2nd one, then I can use it on that one? Otherwise it does help with the tracking of the litter because they only have one way out, thru the front and it causes them to track a lot less litter. I would highly recommend this dome to anyone who's cat will allow it. It is a big help.