An award-winner and thru-hiker's delight, the Outdoor Research Helium Rain Jacket is our ultralight and ultra-packable pick for an emergency shell that we can stash away for surprise showers, windswept vistas, and drizzly descents. The thin Pertex Shield Diamond Fuse 2. 5-layer is surprisingly durable for its weight and keeps our weather protection as light and breathable as possible for our calorie-burning pursuits in the wind and rain. We like other Outdoor Research shells better for consistent rain and downpours, but it's hard to beat the Helium's 6-ounce weight and its packability when we stuff it into its zippered chest pocket to hog less of our precious pack space. The Helium more or less lives in our pack, so we always have easy access to some waterproof and windproof protection on our hikes, trail runs, and backpacking trips.