SpeedySift Cat Litter Box with 56ct Disposable Standard Sifting Liners, 11 Corrugated Plastic Board High Sides, for Cats Up to 20 lbs

Innovative offset-stacked liners: Each liner acts as a sieve. When two are offset and stacked together they form a solid base which prevents urine leakage and litter from falling to the bottom.
Ingenious QUICK & EASY high-sided lid: Clamps up to 15 liners in just one second, eliminating the use of drawstrings or rubber bands. It also prevents cats from pulling the liners into the box. Made of light-weighed, highly-durable & weatherproof corrugated plastic. It is100% plastic, not cardboard or plastic coating!!!
Replaceable side walls: Best for messy cats! Most cats are not likely to soil the sides, but some cats do. Although it is easy to wipe off the dirt with wet tissues, if you don’t like to clean, you may choose to replace the soiled side walls with a new one. Side walls replacement is available on Amazon.
Use with clumping clay litter that is non-lightweight. According to the Humane Society, most cats like a shallow bed of litter, so provide 1 to 2 inches of litter rather than 3 to 4 inches.
Ideal for cats up to 20 pounds.