Oatey 39220 2-Inch by 3-Inch Sure-Vent Air Admittance Valve 160 DFU with 2-Inch by 3-Inch PVC Schedule 40 Adapter， White<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Complies to ASSE Standard 1050 and 1051.</li><li>For use as a secondary vent.</li><li>One size approved to handle up to 4"" vent pipe.</li><li>Opens/closes as needed by building's plumbing system.</li><li>Air admittance valve</li><li>For use as a secondary vent</li><li>Opens and closes as needed by building's plumbing system</li></ul></div><img src="http://ecx.images-amazon.com/images/I/31r9U8S9y3L.jpg" noproxy>