Puredrop PDR-FA15 alkaline water filter contains natural mineral balls, calcite, and corosex to restore calcium, magnesium, and potassium ions. It raises pH levels and provides clean and great-tasting water for your loved ones This alkaline water filter is a great add-on for under sink water filters or reverse osmosis systems Puredrop PDR-FA15 alkaline water filter is equipped with push-fit connections and fits 1/4” tubing Please note: mineralized RO water will slightly increase the TDS of treated water Register online to activate your extended manufacturer and lifetime free tech support from U. S. local support team. We stand behind our products and if you encounter any problems with any of our products please reach out to us immediately. We are happy to help