Perfect foundation for more performance. Wear it under your sports shirt or on its own. In any case, this pleasantly lightweight Decision Layer optimizes your skin climate management. It cools when you sweat and warms when you are cold. The legendary 3D Bionic Sphere System supports you at the chest and back in its "ThermoSyphon expansion stage." Enjoy more comfort, endurance, and performance. This product from the X-BIONIC-4.0 generation is made using ultra-high-definition Retina technology. You can feel it in its high effectiveness density, intense functional transfer, and precisely defined functional zones. Supported by the interplay of numerous technologies: Sweat Traps quickly transport moisture via the Air Conditioning Channel to areas with intense evaporation. The Aircomplex Zone at the sternum and ventilated Air Guides help rapidly transport warm, humid air away from the body.