Drinkwell® Replacement Carbon Filters (4-Pack) by PetSafe - PAC00-13906
Amazon.com : PetSafe Drinkwell Premium Replacement Carbon Filters, Dog and Cat Water Fountain Filters, 3 Pack, Black and White : Replacement Refrigerator Dispenser Water Filters : Pet Supplies
Pet Supplies : PetSafe Drinkwell Replacement Carbon Filters, Dog and Cat Ceramic and 2 Gallon Water Fountain Filters, 4-Pack : Pet Self Waterers : Amazon.com
3 x PetSafe Drinkwell Replacement Charcoal Fountain Water Filter Cartridges Pack 679562707100 | eBay