Oatey Sure-Vent PVC Air Admittance Valve a reliable solution for your plumbing ventilation needs with a 20 DFU (Drainage Fixture Unit) capacity. This valve complies with ASSE Standard 1050 and 1051, making it suitable for use as a secondary vent in plumbing systems. Designed to fit one size that supports up to a 3-inch vent pipe, it efficiently opens and closes as required by the building's plumbing system. The valve is available in sizes ranging from 1-1/2 to 2 inches, crafted from durable PVC material, and is packaged individually in a box for convenience. Its design ensures optimal performance on diameter branches up to 3 inches, providing a dependable and easy-to-install ventilation solution for your drainage system. Model Number: 39016