The Outdoor Research Helium II is essentially a cross between a super light rain jacket and a wind shirt; it offers the extended water resistance of a rain jacket with the weight and packability of a wind jacket. This model is the most compact jacket we tested, and it conveniently stows into a special built-in stuff pocket. It might lack the durability or the ventilation options to make it as versatile as several other options in our review, but for backpackers, hikers, climbers, and trail runners who might leave their jacket in their pack 95% of the time, the Helium II is a perfect option.
This contender is the lightest and easily the most packable of all the models we tested, making it ideal for moving light and fast, or to carry around as a just-in-case layer for protection against unsettled weather. We found our Top Picks and Editors' Choice winners, the Outdoor Research Foray, REI Rhyolite, and Arc'teryx Beta SL, all performed better during blowing rainstorms; all three offered better breathability, but none packed down nearly as small and were all twice the weight of the Helium.