Our Helium Bivy used to be the best-selling, award-winning, lightest shelter offered by Outdoor Research – until we outshone it with this: The newly renovated Helium Bivy is significantly lighter than its previous version, the Helium Bivy is ideal for multiday minimalists who are looking to trade weight for speed, agility, and performance.Thru-hikers and bikepackers love the new Helium for its refined footprint and reduced weight, and trust it for its feathery waterproof and breathable Pertex Shield+ fabric that doesn’t compromise on durability. A no-nonsense clamshell opening is sure to handle seasons of adventuring to come.