The AXEON HYDRO 2-Pack Dry Membranes are a top-of-the-line RO membrane designed for use with the AXEON HYDRO 750/1250 Reverse Osmosis System. With high quality construction and optimal rejection capabilities, it ensures clean and purified water. Upgrade your filtration system with confidence. Filter & Membrane Replacement Schedule: Hyperfiltration Membranes: Replace after 6-12 months EZ Twist Cartridges: Replace after 3-6 months / Minimum of 6,500 gallons of purified water produced