The function of the Vent filter is to maintain near ambient pressure in the tank as well as ensure the tank sterility. It can remove the viruses and microorganisms and has been designed to be less operative than HVAC filters. Also, Vent filter can prevent the insects from crawling in as well as out of the vents. It is really simple to recover small items released into the vent. This is strong enough to block the larger debris and prevent the activities of insects.