Textiles with schoeller®-PCM™ contain innumerable tiny microcapsules filled with Phase Change Materials (PCM). These microcapsules react to temperature differences by altering their aggregate condition from solid to liquid and vice-versa. The Phase Change Material in the microcapsules has been set to a particular temperature range. If the body temperature or the outside temperature rises, the excess warmth is stored. When the temperature drops, the previously-stored warmth is released again.