Specification: Condition:New Material:Cotton+Activated Carbon+Ion Exchange Resin Product Name: Pet Fountain Filter Quantity: 4PCS Color: White Size: 5 x 5 inch Shape: Square Round Pattern: Solid Applicability: Cat dog other animals Triple Filtration System: 1.Strong Fiber Cotton High-Density Cotton Mesh Surface Layer Filters out hair sediment and debris to clean water. 2.Activated Carbon Activated Carbon Purify and freshen drinking water for better tasting. 3.Ion-Exchange Resin Ion-exchange Resin Reduce the heavy metal ions in water and soften tap water. Package Included: 4Pcs Cat Water Fountain Filters