These filters (4-pack) are suitable for the Petsafe Current Fountain. Drinkwell replacement carbon filters keep your pet's drinking water clean and fresh. Each filter features a double-density polyester fabric that traps hair and dirt, while the charcoal removes bad odors and odors from the water, making it more attractive to drink. Filters help extend the life of your fountain and pump and should be replaced every 2 to 4 weeks for maximum freshness.