Pet water dispenser filter element replacement filter cotton [Quadruple Filtration System] Each blue and white L-shaped cat water dispenser filter element consists of a pre-filtration foam layer, a high-density porous cotton filter layer, high-quality activated carbon, and ion exchange resin. The cotton layer filters hair, sediment, and debris. The activated carbon eliminates bacteria and chlorine odor. The ion exchange resin softens tap water and helps prevent urinary tract diseases. [Improved and More Adequate Materials] The blue and white filters for cat water dispensers are made from high-quality bulk filter material that is non-toxic, visible, easy to use, and clean. Each L-shaped dispenser filter material is individually packaged and stored properly for optimal results! The filter elements have been fully upgraded with increased quantity and quality to more effectively enhance cleaning power. [Replacement Cycle] To help prevent water splashing and dust, rinse the filter element thoroughly with tap water and soak for ten minutes before use. Clean it weekly and replace it every 2 to 4 weeks to maintain water cleanliness. Always store the filter with the flat surface facing up for optimal filtration.