Lexair KEYSTONE® STAINLESS STEEL VENT VALVES are manufactured to the NAVSEA standard 804-1749102/1749103 Rev C. They are offered in both round and oval style bodies and feature a working pressure of 15 PSI (45 PSI hydrostatically tested). These “MADE IN THE USA” products were designed to be used as an airtight or watertight closure as well as for use fire dampers. They are compliant with several MIL Specs and are used on all NAVY ship classes. They are available in 2-1/2” through 36” round or 7x3” through 30x20” oval sizes. They are typically used for HVAC controls, intake and exhaust air applications, lithium-ion battery storage venting or any application where a firesafe damper is required.