The “Universal Litter Box” was designed with high walls to benefit both male and female pets. Since most litter boxes are used for female pets, litter is used to cover a pet's relief, whether it be urine or feces. It may not be all the time, but as usual, it is when you have company. No matter where you put the box, the company will end up walking on the litter! Hopefully, it is not with their bare feet! Having high walls can prevent the litter from flying out of the box when dispersing from the pet's paws. Also, male dogs like to lift their legs when urinating. This makes high walls an option for them to use for training. But, when using the “Tree” or “Fire Hydrant” in the litter box, the high sides will help prevent the urine from ending up on the walls and floor.