Union Expansion Rubber Joints meanstwo Galvanized Iron Unions connected with double EPDM or NBR spheres, then screw with pipe through female threads. This product is widely used in chemical, construction, water supply, drainage, petroleum, light industry, freezing, sanitation, plumbing, fire protection, electric power and other basic engineering due to its good comprehensive performance.They adapt to a variety of media and the environment. Operating Conditions :Operating Pressure:PN10PN16Explosive Pressure:3.04.5MpaVacuum Rating:400 mmHgTemperature :EPDM:-10to 120 NBR:-10to 82Neoprene:-10to 110Medium :Air, Water, Sea Water, Hot Water, Oil, Acid, Alkali.