The PVC DWV flush closet flange features a pipe stop and fits inside 4-inch DWV pipe and over 3-inch DWV pipe. The flush closet flange also features a knockout to prevent debris from entering the draining system. The closet flange is secured to the floor of the dwelling so that a toilet can be affixed to it and allow for a pipe connection (under the floor) to continue the piping for evacuation of the used water. Please refer to NIBCO technical data sheets and catalogs for engineering and installation information. Polyvinyl chloride (PVC) is the most frequently specified of all thermoplastic mate