Exchanger mask FHC with Scent-Lok. Breathe Warm. Conceal Scent. Marries two industry leading technologies. Made of fleece and lined with Scent-Lok ClimalFx fabric. To produce the must have piece of winter gear. Inside every Exchanger Mask is a patented heat exchange module. As the user exhales, the air leaving the mouth is directed from the mouth-port through the chambers of the heat exchanger module, which stores the heat and water vapor from the exhaled breath. When the user inhales, the co