We use the storage containers, but I cut an opening in one end. They only have two step over a 5 inch door. Some of our kids are flingers and will shovel a ton of litter each time. I have foound that you can put the lid on and it keeps some of the smell down. For our larger guys ( Bart, Mits, Peak) it usually keeps the aim in the box. A regular litter pan is way to small for a 20+ lb cat. These guys will shoot 6 inches over a regular pan.