Specially designed insulation panels work with most standard window units to a seal that prevents energy loss and improves overall cooling / heating Made with EVA foam and aluminum foil, this window insulation excellent thermal insulation properties, dustproof protections, and durability The aluminum foil window insulation Set effectively reflects sunlight and heat to maintain indoor temperature while providing waterproof protections for your air conditioners unit Easy Installation: suitable for 5000 to 22000 BTU window air conditioners simply measure your window space, cut the foam pieces to size, and achieve perfect sealing around your unit Helps retain cool air in hot weather and warm air in winter while reducing operational and eliminating cold drafts for enhanced comfort and energy efficiency