The 308 Series Commercial/Industrial insulated steel garage doors are rugged and beautiful. They are designed to have a sleek and appealing appearance with great weather resistance. The Model 308 door is made with a sandwich type construction, steel outer skins are formed and then pressure bonded to a polystyrene core giving the door maximum strength and superior insulating efficiencies. Two insulations are available, R9.1 or R12 with optional 3# density EPS foam.