The Original Drinkwell Fountain, designed for cats and small dogs, supplies fresh filtered water for your pet. The Drinkwell Original Pet Fountain uses an innovative watering system featuring a patented free-falling stream of water and holds 1.5 litres of water. Flow control is adjustable. A large replaceable charcoal filter helps remove bad tastes and odours, giving your pet the best possible and most appealing way to stay hydrated. Simple, safe and proven to benefit your pet's health! Research shows that one of the best ways to improve your pet's health is to get them to drink more water and the best way to do that is with the Drinkwell Original Pet Fountain. No assembly is required. For optimal performance of your fountain and the greatest health benefits for your pets, we recommend replacing the filter once every 2 to 4 weeks. The replacement charcoal filters come in a pack of 3 and effectively reduce bacteria and odours in your pet's water.