Large Capacity 1 Way Vent CNA

Provides pressure equalization in roof system
Low cost, all-metal breather used for venting all types of insulation 
Spun from heavy gauge aluminum 
An extra wide base opening and security attached cap 
An optional foam insert is available to prevent moisture from condensing on the inside of the standpipe 
Simple & easy to install 
Unique cap design shields against entry of wind-blown rain or snow 
Flange may be coated with asphalt priming or PVC
This is a one way vent, allowing air to escape only.
CNA = Cap Not Attached