WHEN NATURE CALLS, STAY INDOORS - Imagine if YOU had to brave the elements every time nature called. That s ruff! With our Pup En Suite dog litter box, indoor potty training for dogs is easy pee-zy lemon squeezy. NO FUSS, SMART DESIGN, PATENT PENDING - Four walls and a sloping edge mean NO spray and NO leaks. Each wall slots easily into the dog pee pad holder base. You can decide which one to leave open. Fits into any space.