BUD Industries IPV-1116 IP32 Air Vent, 3.9" x 3.9"
Brand: BUD Industries
Color: Original Version
used to equalize internal and external temperature and pressure, and to prevent internal condensation.  
Vent comes with housing, gasket, and locking nut
Design to meet IP32 protection level
Made of Gray Polycarbonate (PC) reinforced with 10% fiberglass