The distinctively shaped Vango Cobra 400 offers an extremely lightweight option for trekking or those out for an adventure where they can pack light and get around faster. With a Welded Box Wall construction, box shaped baffle channels filled with down ensure maximum loft and an even distribution of down from head to toe. It has also been engineered to ergonomically fit around your head and shoulders for improved heat retention. The Cobra has a 20D 380T Nylon Outer Shell fabric which is durable and water-resistant, enhancing its longevity. It also benefits from Thermal Reverb which radiates your body heat for maximum warmth and comfort.. Insulation and Compression. The Vango Cobra 400 sleeping bag is insulated with a synthetic filling called 'Insulite Helix'. This type of insulation is designed to be both lightweight and warm, making it ideal for outdoor activities such as camping, hiking, and backpacking. Insulite Helix is a high-quality synthetic filling that provides warmth and comf