A bivy sack or bivy shelter is a bit of a riddle—both sleeping bag and tent, and at the same time not truly either of those things. At its most basic, a bivy is a personal shelter for backcountry hikers, climber or skiers who are more concerned with their objective than they are with spending relaxed time in a tent. It’s a bare-bones, protected place to sleep.A bivy is just larger than a sleeping bag, about the same size and uses tent poles to create a minimalist shelter—in essence, it’s an outer shell for your bag that’s built (usually) with waterproof-breathable fabrics that repel nasty weather. It’s the shelter of choice on alpine climbs, big-wall expeditions, solo through-hikes and other adventures where it just doesn’t make sense to haul a full tent.

Outdoor Research offers a full range of bivys for varied adventures. Just remember that when you shop for one, there will always be a trade-off between features and weight. A light bivy sack will stuff into a small package, but it won’t be as comfortable or protect you as well as a somewhat heavier, bulky model if you get caught in a severe storm. So when you are in the market for a bivy, first decide whether you need a full shelter or simply a rain fly for your sleeping bag. To that end, each one of our bivys offers a range of technical features that correspond to its weight and intended use.

The Helium Bivy is our 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.

For warm climes, where you simply want to keep the insects at bay, the Bug Bivy™ provides a waterproof nylon floor and mesh, no-see-um netting overhead.

Again, the key to buying a bivy is deciding what balance you want to strike between comfort, protection and weight. No matter which route you choose, you’ll be traveling incredibly light without foregoing the safety of shelter.

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