The bubble foil insulation has a layer of the Aluminum outside, and with the bubble layer inside, that is used for applications in metal buildings, pole barns, basements, crawl spaces, and many other places. It's soft to cut and install. The Aluminum layer is 95~97% reflective which means it does the exact same job at preventing radiant heat gains in your building. On the other hand, it is a cost-effective way to keep your building cool in the summer and warm in the winter. The bubble design also can affect vibration dampening, vapor barrier and waterproof.