A little small for most regular flat litter boxes we found, the building process was confusing with a lot of unnecessary parts, and left small gaps. Super weird way to build it. Could have just been holes and screws and it would have been so much easier. Some smaller screws they didn't even have holes to go into even though it was the right place. Tip: if there's no hole where it needs to be hammer the screw in part way and then drill it in after. It won't drill in otherwise.