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Streamlined ThermoBall™ powered by PrimaLoft® baffles are contoured to fit and flatter your body. This insulated vest will maintain your core warmth in cold, wet conditions. Our synthetic insulation technology features round ThermoBall™ clusters that trap and retain heat to achieve phenomenal warmth without weight. Wear this thermal vest as a mid-layer for added warmth on the coldest winter days, or pack it for emergency protection in the backcountry.
Developed in partnership with Primaoft, Inc., ThermoBall is a revolution in insulation technology. Unlike traditional continuous-filament synthetic insulation, the small, round PrimaLoft synthetic-fiber clusters closely mimic down clusters, trapping heat within small air pockets to retain warmth. Independent clo testing by Kansas State University has shown that ThermoBall has warmth equivalent to 600 fill goose down. As a result, ThermoBall can offer the lightweight warmth and compressibility of down with the wet-weather insulating performance of synthetic insulation.