Ultralight yet super warm, highly insulated yet extremely packable. The Ionosphere 5 offers the perfect balance of low weight and comfort for fastpacking, thru-hiking, and multi-day mountaineering in challenging environments. This insulated air mat is equipped with all the tech to keep you warm when the temperature drops, with a combination of heat-reflective TILT and Stratus™ R insulation to reduce heat loss through radiation and convection. The result is an exceptional warmth-to-weight ratio, allowing you to catch vital rest in cold conditions, even when pack space is at a premium.