The Drinkwell® 360 Replacement Filters keep water clean & fresh and are designed to fit Drinkwell® 360 Fountains. The cylindrical filter features a pull-tab for easy placement and removal. The filter contains granulated carbon for extended filtration and the duo density polyester pad captures debris. Filters should be replaced every 2 weeks.Features 3-pack of cylindrical filter with pull-tab for easy placement and removal Charcoal Filter removes bad tastes and odours Constant circulation helps inhibit bacteria growth in between cleanings Filters extend the life of your fountain Replace filter every 2 to 4 weeks.