Portals Plus insulation Breathers and Vents are used to prevent moisture vapor from becoming trapped in the roof system. They equalize air pressure and reduce 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 them. Both the Breather and Vent are available in heavy gauge spun aluminum or black, high-density polyethylene with a locking, vandal proof cap that shields against entry of wind, rain or snow.