Engineered for lightweight thermal efficiency, the Sierra Thermal Vest is the essential layering solution for any outdoor adventure. Stormtech Thermal Shell™ insulation provides lightweight warmth, while a windproof outer shell helps maintain thermal performance by keeping heat in and wind out. A DWR water-repellent finish repels light moisture. Built for added protection, a full-length internal storm flap, and adjustable hem help block wind and cold.