... steel.The before and after protective film treatment,together with high precision pressure-shaped gravel ensure the roof ... to be the best roofing material.Coated with an alloy composed of Al55%,Zn43.4%,Si1. ... 6%,with Non-toxic acrylic adhesive and natural stone,Color ... provide permanent technical support and after-sales service with our customers.6.We warmly welcome you to ...