Perfect base for enhanced 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 you when you freeze. Supporting you at the chest and back is the legendary 3D Bionic Sphere System in its "ThermoSyphon expansion stage." This product from the X-BIONIC-4.0 generation is manufactured using ultra-high-resolution Retina technology. You can feel this in its high effectiveness, intense function transfer, and precisely defined functional zones. The Aircomplex Zone at the sternum, along with ventilation-optimized Air Guides, helps quickly transport humid warm air away from the body. The ergonomically optimized Ideo Waistband waistband with a higher cut line in the back area keeps your shirt in place even during constant movement.