Oster Fresh Sips Less Stress Cat Fountain with Continuous Flow, 100 fl oz (BPA Free) 100 oz capacity; perfect for a small dog or up to two cats. Continuous flow means continuous filtration, healthier and cleaner water for your small pet. No drip reservoir means refilling the tank is easier with no mess. The fountain reminds and encourages your small pet to drink more water. Includes (1) charcoal filter that reduces impurities in the water, and (1) particle filter that helps capture hair, food, dirt and other debris.