Watts Water Technologies N36-M1 1/2" Water Service Vacuum Relief Valve Brass body construction with NPT male inlet connection, and a protective cap CSA certified 1/2" Vacuum Breaker Maximum Working Pressure: 200psi (13.8 bar), Maximum Steam Pressure: 15psi (103 kPa) For use in water heater/tank applications to automatically allow air to enter into the piping system to prevent vacuum conditions