The Smart Check? provides you with reliable back-flow prevention without the inline restriction of a conventional check valve. With the use of high powered magnets, the Smart Check valve remains in the closed position to 2 PSI, opening fully when 1/2-lb. line pressure is exceeded. The Smart Check has a Spring-Loaded gate mechanism allowing the valve to be installed in any orientation. Plumbing Connection: 1" Union x Union Spring Tension: 1/2 lb