【PREMIUM QUALITY】 4 pack high quality activated carbon filters. Size: 5.0*0.4inch. 【SCOPE OF APPLICATION】Replacement water fountain filters compatible with MOSPRO pet fountains. 【PURIFYING PERFORMANCE】 Filter hair and residue, remove odors and soften water, getting better water tasting. 【FREQUENCY OF REPLACEMENT】 We suggest to replace it 2-4 weeks to keep the water fresh and clean. 【NOTE】 To help prevent the charcoal dust from shedding, please rinse filter with water thoroughly before use, providing the clean water for cats and dogs.