Conquer the peaks of ambitious performance sports with the X-BIONIC® ENERGY ACCUMULATOR 4.0 SHIRT ROUND NECK LONG SLEEVE WOMEN. The new 4.0 generation is the first to offer Retina® Ultra-High-Definition quality for unique functional accuracy. The patented 3D Bionic Sphere® System with ThermoSyphon® technology is more powerful than ever and works on the chest and back: Complex 3D structures and Y-shaped elements maximize air exchange, cool you when you sweat and warm you when you freeze. Functional zones such as the Air-Conditioning Channel® and the AirComPlex zone in the upper abdomen, as well as ISO-shoulder and Sweat Traps® under the arm, are also part of the performance-enhancing thermoregulating technologies. Expansion Ribs® at the elbows ensure optimal climate comfort while providing full freedom of movement.