Specially designed for Catit Design SmartSift, these biodegradable replacement liners make managing your cat's litter very convenient. Easy to install, the liners are designed to fit perfectly in the cat pan base. They are very effective at preventing waste clumps from sticking to the surface of the base, making cleanups so much easier. When the liner is full, simply remove and discard it. The liners will degrade in an organic or regular landfill.