Triple filtration system and grinding filter: Mesh (PP cotton - filters hair and other impurities), activated carbon filter (absorbs odors and residues), ion exchange resin, and water circulation filter. Intelligent working mode - Equipped with a light sensor and a water volume indicator, the water fountain can automatically adjust the frequency of water flow between day and night when operating in Smart Mode, a quieter and energy-saving mode. In Normal Mode, water will continuously bubble to ensure that your pets always have access to water, especially after intense activity. Low water alarm and automatic shut-off at low water levels. Filter replacement notification - The filter control light indicates when the filters need to be replaced. Ultra-silent system - The noiselessly designed pump and unique, twisted water flow provide a special and quiet experience for pet owners. Capacity: 2 L, ideal for small to medium-sized pets. Requires a USB power supply, not included.