The Hydronix mh03-1812wh membrane housings are manufactured with high-quality nsf approved material and will accommodate standard membrane elements. The dual double O-ring design ensures a leak proof connection. Installs in minutes to any standard ro system that uses 1/8 inch NPT connections. Adapters can be used to convert the 1/8 inch port to any size needed. This membrane housing can be used with any brand systems. Nsf standard 58 certified for use in reverse osmosis water treatment systems. Materials of construction: polypropylene housing and cap - epdm O-ring. Specifications: 1/8 inch NPT ports - Max temperature 125°f (51.7°C) - Max pressure 100 psi (7 bar).