Compatibility: Replacement filters and pump sponges set, perfectly for 7L/1.8Gal dog fountain(FN-W05) 4-Layer Filtration System: Pet fountain filters come with 4-layer circulating filtration system. High density cotton layer, coconut shell activated carbon and ion exchange resin can absorb impurities, hairs, debris and heavy metals in water, making every drop of water healthy for your pet Pump Sponges: High density sponge can further filter out impurities and hairs, preventing them from entering into pump, it can help extend pump life Frequency of Replacement: It is recommended to replace filter and sponge every 2 to 4 weeks, please change them more often if you have multiple pets Warm Tips: Before replacing filter, please soak the filter for 5 minutes in the clean water, and then rinse filter thoroughly, which and prevent carbon dust shedding and overflowing Specifications: 12+12 Color: As Shown Material: Non-woven fabric Package Contents: 12 * Cat Water Fountain Filters 12 * Sponges Foam Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.