GF Piping Systems PVC Pipe Fitting, Flange, Schedule 80, Gray, 4" NPT Female Flange for joining pipes or connecting valves in a piping system Female NPT threads for connecting to male NPT threaded pipes PVC for chemical and corrosion resistance, high strength, and less weight than fittings made from metal Operating temperature range of 0 to 60 degrees C (32 to 140 degrees F) Meets ASTM D1784 and D1785 standards for quality assurance, and meets NSF standards 14 for plastic piping and 61 for potable water service