This anti-siphon pressure vacuum breaker, 1/2 IN, prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage. It consists of bronze body construction, silicone rubber check valve disc, stainless steel springs, plastic check valve seat, a bonnet with silicone rubber O-ring seal, a lightweight plastic disc float, tee handle shutoff, and test cocks for winterization draining. It is ideal in health hazard continuous pressure applications such as irrigation systems and industrial process water systems where the water enters the equipment at or below its flood rim. The maximum pressure is 150 PSI (10.3 BAR) and the minimum pressure is 15 PSI (55kPa).