Window Air Conditioner Covers for U-Shaped 8000/10000/12000 BTU Unit, 3 Layers of Insulation with Aluminum Foil Outdoor Window AC Covers,Outdoor Air Conditioner Covers for Window. 【Thicken 3-Layers AC Cover】 winter window ac cover are made of 3 layers of insulation with aluminum foil, thicken heat insulation middle layer,dustproof and weatherproof.outdoor rated premium material for superior long lasting protection.