Check the listing for details. Aqualine Brass Atmospheric Vacuum Breaker. Condition: New. Listed at 22.87 USD. Brass Atmospheric Vacuum BreakerDurable Brass Atmospheric Vacuum Breaker with female pipe thread inlet and outlet connections. Vacuum breakers are used to prevent back-siphonage of water into the water source reducing the risk of contamination of potable water. These are installed downstream of valves, above highest water flow, and must be in an upright level position, with inlet at the bottom and outflow at the side. Vacuum breakers are not rated for constant pressure and must be installed after valves or controllers.Installation/Operational Tips: Water may release from the vent during normal operation; Protect from freezing by surrounding with a protective enclosure, purging the valve, or other appropriate winterizing methods; Do not install pumps, valves, or other items that may create a source of back-pressure downstream of the vacuum breaker; Do not subject the AVB to continuous pressure for more than 12 hours. Brass contains trace amounts of lead. Not for potable water use. Wash hands after handling