A bivy or bivy-sackor is a lightweight protection device most commonly used when camping outdoors. The bivy should be large enough to fit over your sleeping bag and offer extra protection from the weather. The bivy comes in a range of materials and fabrics, but its waterproof capabilities are a big factor when deciding which type of bivy to choose. Think of the bivy as a tiny tent for you and your sleeping bag.

When hiking and backpacking, the amount of weight you are carrying can make a noticeable difference. A bivy can be made from very lightweight material and can weigh less than a tent’s groundsheet. The material should be breathable to eliminate condensation, but also waterproof to keep your sleeping bag from becoming damp.

An excellent bivy should be big enough to allow for additional layering on top of your sleeping bag. It should also have enough room to store some extra gear. The bivy should ideally have loops that can be staked down to prevent it from blowing away in high wind conditions.

Some types of bivy come with an attachable hood. The hood is usually large enough for a small pillow and some extra tools, such as a flashlight or a water bottle. The hood can also be made from mosquito-resistant material. Alternatively, mosquito-resistant netting may come down over the front of the hood and be attached at the sides with Velcro or a zipper.

The bivy is an excellent option to add warmth when sleeping outdoors. It can be found in the backpacks of the most experienced hikers. A more sophisticated bivy uses materials such as silicon and Gore-tex. The bivy cannot guarantee protection in torrential downpours, but it is shower and rain proof. A bivy is most beneficial when some shelter has been found, such as a cave that has heavy condensation.