1.Fine tensile strength , elasticity , small change in sizes when heated ; 2.Easily welding , firm and secure ; re-weldable after weathering within their lifetime; 3.Fine resistance to ultraviolet property on account of their light -colorized surfaces ; 4.Resistance to root-penetration and chemical corrosion; 5.Fine resistance to weathering and ageing; 6.Keep good flexibility under low temperature (-20 C). 7.Puncture resistance and nice adhesion under shear condition.