Fourteen Pack, one - two 365 days supplyAll NSF Certified Water FiltersUniversal match for any typical RO systems4pcs five micron 2.5" x 10" Sediment Pre Filter; 4pcs five micron 2.5" x 10" UDF Pre Filter; 4pcs five micron 2.5" x 10" Carbon Block Pre Filter; 2pc Post Inline Filter (Polish Finishing Filter) GAC 1/4" NPT ports100 % Compatible with APEC, iSpring, Express Water as well as many more brands. Hydronix five Stage RO Reverse Osmosis Water Filter Replacement NSF fourteen Filters 1 2 yr Supply one - two Year (fourteen air filters) source of RO Reverse Osmosis Filters. Many carbon air filters are Premium NSF Certified Hydronix. This general set s appropriate for just about all key RO Systems with regular dimension housing. See list below for additional details. In case you don't find out your system mentioned allow us know and then we are going to confirm for you. Suitable RO operating system: APEC, iSpring, Express Water, US Water RO Systems, US Water Galaxy, US Water Aquapurion, Watts five stage devices, Purevalue, Nelson, Isopure, Tier1, Hydronix, Max Water Systems, AQUARIUM, Titan Water Pro, Home Pure, Premier Water System, Blue Wave, and most traditional five phase RO Systems. In addition Compatible With :, W-525, RO550-W, Tier1 RO5-WF, GTS-550, ISO-RO5, 200-GX-5050, NRO05-50, GTS-550S, 5EZ50, along with More.