Spears 835-BR Series PVC Pipe Fitting, Adapter, Schedule 80, Gray, 1/2" Socket x Brass NPT Female Transition fitting for connecting plastic and metal pipes Female NPT threads on one end and socket opening on the other for connecting two pipes PVC socket on one end and brass threads on the other for strength, resistance to corrosion, and for connecting plastic to metal fittings Internal O-ring seal for expansion and contraction compensation between different materials Meets ASTM D1784 standards for quality assurance