The poly steel fittings are made of black fittings UL/FM listed and lined with propylene (PP) via injection machine with outside epoxy coating, used to connect with poly steel pipe by thread. The working pressure is up to 1.6Mpa and size available is from 1/2"(15mm) to 4"(100mm). And they comply with the specification of CJ/T137-2008, BS EN10241:2000, BS EN10226-1:2004 and JWWA K116:1987 etc.