Give your furbaby non-stop access to clean, delicious water with Pet Standard PETLIBRO Model PLWF003 Stainless Steel Pet Water Fountain Replacement Filter & Replacement Pre-Filter Sponges! These pet fountain filters are designed for use with the Petlibro Stainless Steel Dog & Cat Water Fountain (sold separately). The triple filtration design includes cotton, activated carbon and an ion exchange resin. Each filter provides one to four weeks of protection against hair and heavy metals while keeping water fresh and tasty. To use, simply soak, rinse and you’re ready to go!