ScoopFree® is the self-cleaning litter box you can leave alone for weeks at a time. It is the only self-cleaning litter box that uses disposable litter trays to provide hands-off convenience and unbeatable odor control. You don"t have to see, touch, or smell messy waste. Simply load ScoopFree with the disposable litter tray pre-filled with Premium Blue Crystals. When your cat uses the litter box, the crystals immediately absorb moisture and odor and begin to dehydrate solids. Twenty minutes later, ScoopFree"s rake automatically sweeps the waste into a covered compartment, leaving the litter smelling clean and fresh. Simply replace the disposable tray every few weeks, and the litter box is just like new. ScoopFree is so reliable it comes with a 90-day money back guarantee.