Marmot

Ion Sleeping Bag: 20-Degree Hybrid

Science can do amazing things—Mars exploration, anybody?—but few innovations are as awesome as the Marmot Ion 20-Degree Sleeping Bag. At well under two pounds, it's nearly as light as Marmot's category leading ultralight down bags, but the Ion has a major advantage: it's filled with a combination of down and synthetic insulation, so it's equipped to handle wet conditions without turning into a soggy, sloppy, and icy mess. Marmot mapped its 850-fill down and Thermal R Micro synthetic insulation to provide ultralight and water-resistant warmth in strategic spots and wrapped it inside nylon mini ripstop fabrics to make sure snags, sticks, and heavy use don't lead to catastrophic leakages.

The Ion is rated to 20 degrees, so it's perfect for shoulder season expeditions where it might rain, snow, or precipitate in ways you didn't know existed. It also features Marmot's dual zipper design, which combines a full-length zipper on one side with a half-length zip on the other, so you can increase ventilation or sit up comfortably in your tent without having to get out of your bag. A wrap-around footbox and drawcord hood also team up to keep your extremities toasty.