APEC FI-CS-2500 Replacement Filter for CS-2500 Water Filtration System US Made highest trustful filtration capacity of similar products. Trouble-free installation with quick twist and lock connection for easy filter replacement. Bacteriostatic for the reduction of heterotopic bacteria. High flow low restriction design to support maximum 1.67 GPM (6.321 LPM) flow rate. Life time tech. support by certified WQA water specialist based in CA.