The Helium Bivy is a minimalist shelter for quick-and-light expeditions, composed of a lightweight waterproof-breathable fabric that weighs only 476g. If you leave the optional hooped pole at home, your shelter weighs only 418g. The clamshell design opens up wide, and removable no-see-um mesh allows you to add ventilation if you're sleeping out at lower elevations in hotter weather.