Newmar RV Sewer Vent Air Admittance Valve 142306Newmar RV air admittance valve sewer vent check for gray water tanks. Made of high quality ABS plastic. Vent is installed under the sink to keep correct pressure in sewer pipes. 1 way valve stops odors. Valve is self cleaning spins to scrub debris off while valve is open. Will want to seal threads with solvent cement (sold separately). Newmar part 142306 Install on 1 1 2 inch diameter ventilation pipe. Black tailpiece measures 1 1 2 inches x 4 inches.