SEP Reflective Insulation Bubble Barrier (RIBB) SEP RIBB consists of two layers of 99% pure aluminum foil laminated to the outsides of one or two sheets of heavy-duty polyethylene air bubble cushioning. These bubbles form trapped air spaces between the foil surfaces to give the structure excellent R-Values. Because SEP RIBB is also impervious to moisture and air currents, an ideal convection and vapor barrier. SEP RIBB's surfaces reflect heat in both directions to keep you warmer in winter and cooler in summer. SEP RIBB with single bubble layer is intended for residential sidewalls, duct wrap, and under-floor radiant heating systems. But SEP RIBB with double bubble layers is intended for walls, floors, and ceilings of all types of buildings, especially suited for post frame and pre-engineered metal buildings. SEP RIBB Insulation products consist of one or two layers of Barrier Bubble material laminated between layers of aluminum foil to provide excellent thermal resistance. The bubble contains an air retention layer designed to provide increased strength and puncture resistance. SEP RIBB Insulation is used to either contain heat for maintaining warmth, or to resist heat for maintaining cold. In many applications, radiation is the dominant mode of heat transfer. foil bubble is considerably more effective than conventional insulations in reducing radiant heat transfer.