Open vents can be very hazardous to your home. This can allow moisture, cold air in the winter, hot air in the summer, and pests into your home.
The black strips in the picture are the patented CarbonArmor used to repair wall cracks. Also pictured is the cover the seals the previously opened vent.
Crawl space vent cover. This completely seals the previously open vent from pests and outside air.
Vent Cover Inside
The SilverGlo vent block seals and insulates the vent cover from the inside.