3 pack Drinkwell Premium Filters feature 6 charcoal compartments which evenly distribute the charcoal for long lasting, deeper water filtration. More charcoal is added to each compartment progressively to maximize water filtration. These filters will work with most Drinkwell Fountain models* and should be changed every 2 to 4 weeks to maintain maximum water freshness.
**These are not compatible with the Drinkwell 360 Fountain Model**
