TankPAC Industries Co., Ltd. is one of the largest pressure tank manufactures in the world today. To provide the high quality tanks and good service to satisfy our customers needs is always our goal. Good is not enough for us; we want to be the best in the industry. TankPAC pressure tanks use a butyl diaphragm and polypropylene liner to separate the water and air. These materials limit the growth of germs and prevent impurities inside the tank. Advantages of a metal diaphragm type expansion tank Metal shell has greater pressure resistance than plastic. Lower molecular porosity of metal eliminates air pressure loss. Diaphragm-type design assure stable water outflow. Features: Stainless steel connection built for Reverse Osmosis water storage tank; pump tank & thermal tank applications. Brass cap with internal O-ring guarantees no air loss from air-vent. Smooth internal air vent cap prevents diaphragm damaged. High-grade butyl diaphragm, post-cure procedure insures a tasteless and odorless water chamber NSF listed. IAMPO approved. CE Mark approved.