I purchased the large and it’s smaller than I was expecting; yes I premeasured to get an idea. If the separator piece was used the litter box would not fit. The quality is very nice though, best looking way to cover a litter box. Unfortunately this went on sale right after I purchased which made me slightly irritated as I would have bought the larger size at the sale price. I got this in about 36 hours from my ordering time, excellent packaging. It arrived with no scratches or dents and looked great put together.