Both types of products contain exactly the same high-quality Aluminum Foil and have the same reflective properties. The primary difference is their physical structure. The application determines which type of product is best. Reflective insulation is composed of one or two layers of pure aluminum, which reflects 97% of radiant heat, surrounded by an inner core of bubble or thin fiberglass. The inner core contains an air-retention layer, which acts as a thermal break, effectively reduces conduction, and provides increased tear and puncture resistance.