Portals Plus insulation Breathers and Vents are used to prevent moisture vapor from becoming trapped in the roof system, equalizing air pressure, reducing the risks of ballooning, blow-off, deteriorating insulation and separating deck seams. The Portals Plus Vents have a one way valve designed in the unit to prevent moisture from re-entering the roof system. The Portals Plus Breathers allow for both exhaust and convective movement of air between breathers.