This is the larger version of the very popular Drinkwell Pet Fountain - and as the name suggests is perfect for Dogs. The fountain comes with a build in additional capacity reservoir which means the unit has a total capacity of 2 gallons and has a large bowl for enthusiastic lapping! The Big Dog Drinkwell offers a fill level indicator, flow control lever and a 5inch wall to help keep water in the bowl. Mains Powered. Includes 1 charcoal filter - replacements are available. Suitable for medium - large dogs.