1.5″ NPT In Line Vent ABS Black Plumbing Air Admittance Valve Drain Vent
It breaks the siphoning action caused by draining water. 1.5-In NPT In-Line Vent. ABS construction.
Oatey 39012 1.5 in. NPT ABS in-Line Vent, Black
1.5-In NPT In-Line Vent. ABS construction.