Outdoor Research Helium Bivy Sack, Pewter. Made from the same fabric as our go-to ultra lightweight rain shell, the Helium II Jacket, the Helium Bivy is the most lightweight bivy we make, weighing in at a feathery 18oz. Featuring a classic, no-nonsense clamshell design, completely waterproof, breathable and ready for many seasons of adventuring–thanks to the 70D floor–the Helium Bivy is a true minimalist bivy for fast and light solo expeditions. Anti-Fungal Coating on Floor. The item “Outdoor Research Helium Waterproof Bivy Sack, Pewter NEW” is in sale since Sunday, November 13, 2016. This item is in the category “Sporting Goods\Outdoor Sports\Camping & Hiking\Outdoor Sleeping Gear\Sleeping Bags”. The seller is “brisk_deals” and is located in Multiple Locations. This item can be shipped to United States, to Canada, to Australia, to Japan, to China, KR, ID, to Taiwan, ZA, TH, to Hong Kong, RU, IL, to Mexico, to New Zealand, PH, SG, SA, AE, QA, KW, BH, MY, BR, CL, CO, CR, PA, TT, GT, HN, JM.