When worn on its own or under a shell, the Patagonia Women's Nano Puff Insulated Vest provides lightweight, compressible, and wind-resistant insulation for your cool-weather romps. The Nano Puff Vest features PrimaLoft Gold Eco insulation, which not only boasts a partially recycled constitution, but it also retains body heat with acute thermal efficiency. And unlike down, PrimaLoft Gold Eco maintains its insulating capacity when wet, which makes this vest an ideal choice when moisture may be a factor.