Coverking’s Custom Triguard Car Cover is best suited for light weather conditions and is comprised of three layers: two thick, strong layers of spunbond polypropylene envelop a middle layer of material made from meltblown polypropylene. We say meltblown because this process, specified and designed by Coverking, consists of melting polypropylene into tiny fibers and then blowing out to where they stick to each other to form a web (think, cotton-candy machine). This mesh-like material has enormous capabilities: namely, it allows air to flow through but does not allow water to penetrate. The outer layers that are spunbond are much stronger as they are formed by a process that extrudes them from the machine onto the roller. Extrusion creates much larger fibers, giving the polymer its strength.