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™.From the manufacutrer:Each year we introduce new, unique, functional products that excite our customers with their creative design. Our goal is to continuously manufacture these products with quality and efficiency to bring value to our customers.