APEC Water high capacity filter set is made in USA with high quality filtration components to provide a longer lasting filter set to protect and prolong the lifespan of your reverse osmosis system. Premium quality pre-filters and 4th stage ph+ calcium carbonate re-mineralization inline filter lasts 6-12 months for high performance contaminant removal and adds high purity food grade calcium minerals to enhance the water taste for people who prefer drinking mineral water. These standard size filters are 10" and feature ¼" quick-connect fittings for durable and easy filter change-outs. These filters are compatible with APEC Water System's counter top reverse osmosis drinking water system (RO-CTOP-PH & RO-CTOP-PHC ).