LIGHTWEIGHT & BREATHABLE: Be prepared for a night of adventure by carrying this lightweight sleeping bag. Made of a combination of nylon, TPU, and polyester, this helium bivy is waterproof, breathable, and easy to carry and use. LIGHTWEIGHT & BREATHABLE: Be prepared for a night of adventure by carrying this lightweight sleeping bag. Made of a combination of nylon, TPU, and polyester, this helium bivy is waterproof, breathable, and easy to carry and use. DURABLE AND BREATHABLE: This Outdoor Research bivy features a fully seam-taped construction that adds durability to it. Its clamshell opening makes it the perfect bivy tent for fast and light missions. HELIUM FABRIC: A highlight of this adult sleeping bag is its ultralight helium fabric, making it an ideal shelter for adventurers who are looking for agility, speed, and superior performance. It comes with a reflective logo and trims. HELIUM FABRIC: A highlight of this adult sleeping bag is its ultralight helium fabric, making it an ideal shelter for adventurers who are looking for agility, speed, and superior performance. It comes with a reflective logo and trims.