Properties 1.Environmental-friendly, no toxin, resistant to corrosion; 2.Endurable high temperature(the highest temperature is 95 centigrade) and high pressure(anti-pressure test intension over 5 MPa); 3.Heat-Melting joining, no leakage; 4.Light weight (only 1/8 of metal pipe); Lower thermal conduction expansion (only 1/20 of metal pipe); 5. Beautiful appearance, both shown fitment and hidden fitment; 6. Good anti-corrosive, lower cost; 7. Long service life, over 50 years under allowable condition.