FOR Ambitious ATHLETES.Feel the soothing effect of lighter and at the same time highly functional high-tech underwear. With its moderate compression, the X-Bionic Energizer 4.0 Shirt Round Neck Women is designed for female winter sports enthusiasts who appreciate outstanding wearing comfort and at the same time value comprehensive thermoregulation. The shirts of the X-Bionic -4.0 generation are manufactured using an ultra-dense knitting technique that positions temperature-compensating functional zones even more precisely. Thanks to constant innovation, the legendary 3D Bionic Sphere system has reached a new level of perfection and, reinforced by Thermo Syphon technology, now provides an even more efficient performance-enhancing feel-good climate.