Worlds Greatest Litter Box! Unique step design removes litter from paws keeping it inside the litterbox and not on your floor. 50 percent larger than average litterboxes (21 .5 diameter x 20 high). The unique shape of the Booda Dome is designed to accommodate cats of every size. Replacement filters and liners available. This item ships Oversize and requires an additional freight charge which is added to the order.