Oatey 1-1/2" to 2" Air Admittance PVC Vent Valve a reliable solution for managing ventilation in plumbing systems. With a 20 DFU (Drainage Fixture Unit) capacity, it complies with ASSE Standard 1050 and 1051, ensuring it meets stringent safety and performance requirements as a secondary vent. Designed to accommodate vent pipes up to 3 inches, this valve automatically opens and closes as needed to maintain proper airflow and prevent sewer gases from entering the building. Its versatile size range from 1-1/2 to 2 inches makes it suitable for a variety of plumbing applications, providing efficient and dependable venting. Model Number: