Based on many years of experience that most of our customers are fiberglass reinforced plastic products manufacturers, the tree pit grates are actually resin gratings made of fiberglass reinforced plastic materials, and the fiberglass reinforced plastic products themselves have good It has excellent weather resistance and can be weathered in the wild for a long time and has a long service life. FRP products are light in weight, high in strength and low in cost. Therefore, fiberglass gratings are generally used for tree pit grates. In fact, a large number of bumpers on cars and cruise ships are now used. Even the car body and hull are made of fiberglass. Hope this helps.