The Helium Bivy is Outdoor Research's lightest, best-selling, and most awarded bivy sack of all time. Incredibly quick to set up and breakdown, the ultralight Helium Bivy is 14% lighter than its last generation, and has everything the outdoor minimalist needs to be comfortable. Thru-hikers and bikepackers love the Helium for its refined footprint and reduced weight, and trust it for its durable, lightweight, waterproof Pertex® Diamond Fuse technology. A clamshell opening makes it easy to get in, get out, and resists wear and tear for future seasons of adventuring to come. This is the ideal shelter for minimalists who are looking to trade weight for speed, agility, and performance.