The Drinkwell Original Pet Fountain uses an innovative watering system featuring a patented free-falling stream of water and holds 1.5 liters of water. The free-falling stream entices pet's to drink more water because it draws more oxygen into the water and constantly breaks the surface tension, keeping water fresh tasting. For added freshness, the included charcoal filter also helps to remove bad tastes and odours from the water. Dishwasher safe (excluding pump). Replacement filters 298-13067 & 298-70710.