The poly steel pipe is the kind of composite pipe
which is made of galvanized steel bonded in the middle with Polyethylene (HDPE) both as  outer and inner layers.  Poly steel Pipe possesses all the good
characteristics of the PE-lined galvanized steel pipe and improves the outer surface
anti-erosion ability.  Therefore, it not only can be apply construction use, but can be
used as under-ground pipe. It has a perfect appearance and has the function to improve
the ability of heat preservation.
The size available is from 1/2" (15mm) to 4"(100mm).
Specification: BS 1387-1985, CJ/T136-2007, JWWA K116:2004