Metallic Foil Bubble Mailers, 15" W x 17" H - 5/Case (Fits in USPS Medium Flat Rate Box) COOL BLUE is the new green! Cool Blue insulation is made with recycled FDA approved plastic and reusable foil. Unlike traditional foam, Cool Blue insulation acts as a shield against the three types of heat transfer: conduction, convection and radiant. The bubbles and poly prevent conduction and convection heat transfer while the foil reflects 97% of the radiant heat. Extra protection! 5/8" foil laminated metalized bubble cushion with self seal adhesive strips. Foil Thermal Bubble Mailers are ideal for overnight boxes. *Pictures shown may vary by size