The Atmospheric Vacuum Breaker is designed to prevent contaminants from entering the main water supply through sprinkler heads. It is not designed to be used as a mainline anti-siphon device.

This 3/4 by 3/4 IN lead free dual check valve backflow preventer helps prevent the reverse flow of polluted water from entering into the drinking water supply at the service entrance or at individual outlets. The valve consists of a lead free brass body construction, with two plastic replaceable check valves, and stainless steel springs. It is designed for non-health hazard residential water system containment, continuous pressure applications and is to be installed immediately downstream of the residential water meter, in a vertical or horizontal position. The minimum working pressure is 10 psi (69 kPa) and maximum working pressure is 175 psi (12 bar).