The litter containers I currently use are $3 plastic tubs with about 2" to 3" of material in them. All of my furkids use them, except three of them. These are plastic laundry tubs I believe. I have use open trays, but the tubs keep them from slinging litter all over the premises. And besides, the cats seem to like the tubs better anyway, because ( I suppose) it give them a sense of privacy. When they use the, all you can see at their level is their heads.

...........wayne