Designed with streamlined baffles that are contoured to fit your body, North Face's ThermoBall™ powered by PrimaLoft® offers ultralight, highly compressible synthetic insulation to keep you warmer in cold, wet weather. Developed in partnership with Primaloft, 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.
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