[Compatibility]Rplacement filters & pre-filter sponges set, perfectly for 84oz/2.5L, blue and grey automatic cat water fountain. [ Triple Filtration System]Cat water fountain filters come with 3 layer filtration system, high density cotton non-woven fabric can fliter hairs and residue, keep water clean; Activated carbon can remove chlorine and odor, purify and freshen water; Ion exchange resin can filter heavy metals and improve the taste, can keep water clean, fresh and tasty all day, and reduce the risk of urinary tract infections. [Pre-Filter Sponges ]High density pre-filter sponge around the pump, can better filter impurities, preventing them from entering into water pump, it can help extend the pump life. [Replace Filter Regularly]Suggest replacing the filter every 2 to 4 weeks and replace the sponge every 4 to 8 weeks; Please change it more often if have multiple pets. [Warm Tips]Before replacing the filter, please soak the filter in water for 2 minutes and then rinse it thoroughly under running water, which will prevent carbon dust from shedding into water, keep water clean. Filters for 84oz/2.5L Pet Fountain Colour:As Shown Material:Polyester Package Contents: 4*Replacement Filters 4*Pre-filter Sponges 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.