[Compatibility] ONLY Compatible with VEKEN 95oz/2.8L Pet Water Fountain. If any doubt, please check product dimensions. [Compatible Pet Filter] Length is about 4 inch. Width is about 4 inch. Thickness is about 0.5 inch. The pre-Filter Sponge: Length: 1.5 inch. Width: 1.1 inch. Height: 1 inch. [Premium Quality Filters] Triple Filtration System: Composed of a cotton layer, activated carbon and an ion exchange resin. Effectively to filter hair, heavy metals, keeps water fresh and improve the taste of the water. [Frequency Of Replacement] To prevent the activated carbon dust from shedding into water, please soak the cat fountain filter in water for 2 minutes then rinse thoroughly under running water before using. 1 to 2 weeks in summer and 2 to 4 weeks in winter. If multiple cats are using the fountain, more frequent replacement will be necessary. [Premium 12 Pack Pet Fountain Filters] 12-pack of premium pet fountain replacement filters and 12 Pack of pre-filter sponges individually packaged and sealed to maintain high quality. Enough supply for 3 to 12 months of use. Replace the pre-filter sponge every 4-6 weeks. The PET STANDARD Replacement Water Filter and Pre-Filter Sponges