The PVC DWV closet flange features a knockout test plug and a hub connection. 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. Polyvinyl chloride (PVC) is the most frequently specified of all thermoplastic materials because of its lightweight, durability and cost-effectiveness. PVC DWV is easy-to-install and is joined by solvent cementing or threading. PVC fittings exhibit high-corrosion and chemical-resistance and will not rust, scale, pit or corrode. NIBCO® plastic fittings are backed by a 5-year limited warranty. Because of its longstanding reputation for innovation and precision in design and manufacturing, NIBCO® is the preferred brand in the industry.