APEC high capacity pre-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 filter set lasts 6-12 months for high performance contaminant removal. 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's countertop reverse osmosis drinking water system (ro-ctop). all us made super high capacity filters 1St stage: high-capacity 10" inline polypropylene sediment depth filter will effectively remove dirt, sand and sediment from the water. 2Nd stage: high capacity 10" inline coconut shell carbon filter to remove chlorine, tastes, odors, cloudiness and colors. About apec for over 17 years, apec has been an industry leading manufacturer who specializes in high performance ro systems. As the original manufacturer, we have dedicated a knowledgeable and sincere team that is committed to providing customer SATISFACTION in hopes to bring many years of enjoyment and good health for you and your family. Apec water does not distribute or sell our products to any 3RD party sellers on Amazon. Please purchase genuine apec water products from Amazon or apec water directly for authenticity.