Fangrui Product Details [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. [ Filter Regularly]suggest Replacing The Filter Every 2 To 4 Weeks And 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 Wat