Navien’s chemical-free, anti-scale water treatment accessory, PeakFlow, is an environmentally friendly alternative to water softeners. It provides protection from scale formation on plumbing surfaces in appliances and hot water systems. The pre-installed inlet ball valve on the 15 lb. (6.8 kg) single cartridge provides easy isolation shutoff and filter changes. Certified to NSF/ANSI Standards 42 and 61.