Oatey 39012 ABS In-Line Vent 2X2  13/16 ABS construction Use to vent drain lines Helps prevent sewer gas from entering your home Push to connect Spring-loaded to open with negative pressure and close with positive pressure Mechanical vent installs on the drain line and vents the line without allowing sewer gas to enter the home Available in either chrome or ABS & packaged in polybag For venting sinks, tubs, Showers, washing machines, etc. Eliminates the need for secondary stacks