4 Pack Pet Water Fountain Filter, Pet Water Fountain Replacement Filtration System Eco-Friendly Cat Fountain Filter Environmental: 4 pcs/pack, replace filter every 2-4 weeks to maintain water freshness. PET Water Dispenser Filter: Charcoal active in the filter can eliminate bad taste and odors, keeping the water clean and fresh. Cotton net: filters the deposits that may exist in tap water, capturing carefully away hair, sediment and debris. Note: Please measure the filter cotton size of the water dispenser before purchase as shown in the picture. For Pet Health: Help filter drinking water, let our pets drink water safely and stay healthy. Features: 1. Pet Water Dispenser Filter: The activated carbon in the filter can remove bad taste and odor, keeping the water clean and fresh. 2. Cotton net: filters the deposits that may exist in tap water, carefully captures hair, sediment and debris. 3. ECO-FRIENDLY CAT FOUNTAIN FILTER: 4pcs/lot, replace filter every 2-4 weeks to maintain water