The PVC DWV P-Trap features a union joint and a hub x female NPT thread connection. The P-Trap provides a water seal so that wastewater will automatically be trapped in the arc of the configuration- thereby preventing unwanted gases from entering the household environment. Polyvinyl chloride (PVC) is the most frequently specified of all thermoplastic materials because of its light weight- 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.