The Xylem-Bell & Gossett 113021 87 Air Vent, intended for 150-pound systems, has a 1/2" female and 3/4" male pipe thread connection. This crucial component functions as an air removal device in HVAC systems, particularly in hydronic heating and cooling applications. The air vent works by automatically removing trapped air from the system, resulting in peak performance and efficiency. https://www.partshnc.com/113021-xylem-bell-gossett-87-air-vent15012f34-mpt