The Solar Eco 1 is built with a complex construction to maximise warmth without bulk. It is insulated with a double layer of Stratus insulation on the upper arranged in a concertina structure to trap warm air. For reduced weight and bulk, the base of the bag has just a single layer of insulation. The elastic internal quilting brings the lining and insulation closer to the user, helping to reduce pockets of cold air. The localised quilting simply means that the stitching which holds the insulation in place has been minimised to reduce the chance of cold spots. Packing down to just 30cm x 18cm, its incredibly low bulk and stashable. Perfect for summer climbing trips, bivis in warm climates, and backpacking adventures.