These vacuum relief valves are are replacement parts for vacuum tanks, vacuum trailers, storage tanks and other pressure vessels. They are made with a durable brass construction. These vacuum relief valves connect using a 1-1/2" NPT and are rated at a 370 CFM flow. They are non-code and and cannot be used on tanks that store or haul corrosives, explosives or combustible materials. Cross Reference Numbers Include: PA7V108B, 366-150