This Resideo Air Vent is designed with a 1/8 inch opening, ideal for various HVAC (Heating, Ventilation, and Air Conditioning) applications. The vent features an EPDM (Ethylene Propylene Diene Monomer) Seat Disc O-ring, known for its superior resistance to heat, water and steam, alkali, mild acidic and oxygenated solvents, ozone, and sunlight (UV). This makes the product highly durable and reliable in a wide range of environments. The air vent's primary function is to automatically purge unwanted air from the HVAC system to improve efficiency and longevity.