This 18x20 Canopy is a very comfortable size for spreading out. It will fit 2 vehicles very easily underneath it. All of our canopy tops are made of polyethylene, which is a form of plastic. They are 6 ounces per square yard, and made with a 14x14 weave count with grommets approximately every 18 inches. They are UV treated for longer protection and have reinforced corners. The silver color is best for shade, as itís made with a black interior. The stripes and white tops will allow the natural light through because they are translucent. They do not allow the direct rays to penetrate. Itís very important that you secure each canopy leg down to the ground using some method for the best protection.