The shape of the globe is ideal for minimizing the amount of litter the cat can kick out. The opening is just large enough for the cat to enter. The globe is lined with a thick rubber material and the screen is coated with the same material. The rubber material prevents and reduces odor absorption by the globe. One of the main benefits of the Litter Robot is that you do not have any rakes or refill cartridges to deal with and you can use your favorite cat litter, no special litter required. Therefore choose the litter robot.