The material is made up of polyester/ glass fabric mat as reinforcement, styrene-bivinyl-styrene (SBS) as modifier and polyethylene film / aluminum film / sand grain / colored sand / sliver as surface coat. There are several advanced colloid grind and thermal conduction oil stove of 1 million-calories power in our factory, which guarantee the quality of our products. Polyester, such as SBS, can be dispersed in the pitch, forming a reticular structure. As a result, the performance of products has been improved, such as high four-way pulling force, good elongation percentage, strong ductility, low temperature proof, aging proof, ultraviolet radiation proof，temperature difference proof, self cured bonding and so on. Especially, period of validity can reach 25 years because of the quality guide line which is very strict in our factory.