The unique patented grill inside the Roll’n Clean™ scoops out the clumped waste, depositing it into the pull-out tray. Just roll the litter box onto its top, and roll back to the up-right position. Remove the tray and dispose of waste! For fast and easy cleaning, use the Roll’n Clean™. The Rollaway is available in two sizes. The large litter box is great for big cats or for multiple cat households.