Helium 600 -4 to -10°CThe Helium 600 is suitable for temperatures as low as 10C and still weighs 1kg! Ideally suited to cold weather and four season camping including use above the snowline. Ultralight shell fabric and high loft down fill on the Helium bags mean higher performance for less weight. Durable 10 by 10 denier, 520 thread count Nylon weighing only 26g m2 with a hot rolled cire treatment to prevent down leakage and increase durability. Premium 800+ loft white