Omega Paw Large Roll' N Clean&trade; Litter Box Simple to use: just roll the litter box onto its top, roll back to the upright position, remove the tray and dispose of waste. Available in large (20" L x 22" W x 19" H with a 9" diameter opening) and medium (19" L x 16" W x 16 1/2" H with a 9" diameter opening) sizes. Imported. One-year manufacturer's warranty.