The Drinkwell Big-Dog Fountain was designed by a veterinarian specifically for large dogs. The Drinkwell Big-Dog holds well over two gallons of water, making it the largest capacity pet fountain on the market, 288-Ounce. Ideal for large dogs and multiple-pet homes, the Big Dog uses the same innovative watering system as the Original Pet Fountain, featuring the patented free-falling stream of water that consumers have come to rely on for cats and small dogs for the past decade. A large charcoal filter removes bad tastes and odors leaving your pet with fresh-tasting, filtered water. The Drinkwell Big-Dog is the best and most convenient way to provide man's best friend with fresh filtered water for days at a time. Drinkwell fountains are compatible with all US 110-volt outlets only and are not to be used with 220-volt international voltage.