Amazon.com : PetSafe Drinkwell Replacement Filter Kit for the Everflow and Outdoor Dog And Cat Water Fountains, Kit Contains 3 Dual Cell Carbon Filters and 1 Foam Pre-Filter - PAC00-13192 : Pet
PetSafe Drinkwell® Fountain Replacement Filters Activated Carbon filters for Pagoda and Seascape fountains at Crutchfield
Amazon.com : PetSafe Drinkwell Replacement Carbon Filters, Dog and Cat Ceramic and 2 Gallon Water Fountain Filters, 4-Pack : Pet Self Waterers : Pet Supplies