This series has been developed for use with primary relief devices on stationary pressurized storage containers with flanged openings. An additional relief valve (excluded from the flow rating) allows the user to service or change any of the valves without evacuation of the container. The handwheel is able to close only the port to the valve being removed, while the rest continue to give proper protection to the container. All manifold flow ratings are based on flow through the relief valves after one has been removed for service or replacement. The “pop-action” valve design ensures high protection and minimal product loss, even at relatively extreme pressures. Rubber plug with chain provided for manifold outlet thread protection. No inlet piping needed. Relief valves automatically reset after discharge. ASME rated for use with LP-Gas and anhydrous ammonia.