Bronze threaded fittings are manufactured from smooth cored castings, designed to provide full flow with minimum restriction. all threads are accurately machined and gauged to ensure a perfect fit with the pipe. all fittings are individually tested under water to ensure quality. Bronze provides a tighter seal and is easier to install than other metals. can be used for water, plumbing, heating, pneumatic and marine applications, able to resist the harmful effects of corrosion when coming into contact with salt water or fresh water polluted with mineral acids or peaty soils. MMM Cored Regular Plug, Cored Regular, Fitting/Connector Type: Plug, 1 in Nominal, Thread, 125 lb, 150 psi, Smooth Cored Casting, Bronze, Domestic