Air admittance valves (AAV’s ) some times called Pro vents are In my professional Not only unprofessional BUT a health Hazard and the stumble bum code inspectors that approve this I think are just looking to line their pockets and to hell with public safety. NOTHING beats Mother natures Natural vent.
Have this garbage replaced and have a real professional vent connection installed. Why rely on cheapo plastic and a piece of rubber for integrity?