FOR Ambitious ATHLETES.Conquer the peaks of ambitious competitive sport with the Energy Accumulator 4.0 Shirt Round Neck Men. State-of-the-art technologies at the highest level increase your performance and strengthen your endurance under all climatic conditions. The high-tech functional underwear for men benefits from the groundbreaking technologies of the X-Bionic -4.0 generation and integrates innovative functional zones in the ultra-thick material, which have a thermoregulatory effect and at the same time guarantee unsurpassed wearing comfort. With Thermo Syphon technology, the legendary 3D Bionic Sphere system reaches a further level of perfection and provides an even more efficient performance-enhancing feel-good climate.