Nemo Astro Air (Riptide Blue) 25L Insulation Type: Aluminized Film Thermal mirror featherweight aluminized film reflects radiant heat. Undulating Lateral Baffles offer the most comfortable and unobtrusive topography for sleeping pads. A metalized film layer provides insulation while maintaining an ethereal weight. The height, stability, quiet fabrics, and paltry weight and packed size make this series the ultimate in ultralight pad design.