The Mountain Equipment Helium 600 is a 3-season bag, EN tested to 15°F. This bag is insulated with ethically sourced 600 down fill. The Helium line features box wall baffles that keep down in place to prevent cold spots. Helium fabrics are designed exclusively for Mountain Equipment and are lightweight and breathable. The lining of the Helium is Mountain Equipment’s softest and lightest next-to-skin layer. This bag is designed with a shark’s toe foot box that allows your feet to lie in a more natural position and a 3-dimensional neck collar to reduce drafts and trap heat. This bag has a ¾ length zipper to reduce weight. Another great feature is the 5-baffle bull’s-eye foot piece; five individual baffles to keep your feet warm and keep the down lofty. The Mountain Equipment Helium 600 is the perfect 3-season sleeping bag; lightweight, high quality materials and construction and a brilliant design. Mountain Equipment has five decades of experience equipping expeditions into the harshest places on Earth.