Warmth whenever and wherever you need it! This breathable and easy-care 2-season synthetic fill mummy sleeping bag is also environmentally sustainable, made with bluesign® certified materials. The Sensofiber micro-fibre fill reflects body heat yet efficiently transfers moisture away from the body and so maintains a wonderfully comfortable sleeping climate. As all synthetic fibres, Sensofiber warms even when damp, is quick drying, easy to maintain and long-lasting. The Sioux 400 XL is a solidly reliable, warm outdoor sleeping bag for trekking and cabin tours in moderate climate zones.