What Our Gearhead® Experts Are Saying:“I grab this when weight actually matters. It lives in my pack on alpine days and comes out fast at windy summits or cold transitions. It warms up quickly, doesn’t feel fragile under a pack, and packs smaller than most jackets this warm.”Cold air moves differently at elevation, and staying warm without slowing down becomes part of the objective. The Helium Down Jacket from Outdoor Research is built for those moments when insulation needs to disappear into a pack and reappear instantly when the temperature drops. We use it on early starts, exposed ridgelines, and long days where every ounce and every layer counts. Pertex Diamond Fuse fabric resists wind, light moisture, and abrasion while staying impressively light, making it reliable under pack straps and during constant movement. Inside, 800-fill responsibly sourced down lofts quickly to trap heat without excess bulk. A raised collar blocks wind at the neck, while the adjustable hem seals warmth when conditions turn sharp. When it’s time to move again, the jacket compresses into its own pocket, ready to stash until the next stop.