Hahn 3-Stage 600 Gallon Undercounter Water Filtration System SELECTIVE AQUAFREE FILTRATION Reduces 66 contaminants while retaining beneficial minerals for optimal hydration. EASY TO INSTALL, REPLACE & MAINTAIN Filter lasts up to 6 months and features easy twist-off design. NSF CERTIFIED Full system certified to NSF/ANSI Standards 42, 53 + 401. 600 Gallons 6-Month filter life