X-Bionic Men’s Energizer Summerlight Briefs - Less weight, more energy. Controlling sweat is good. Taking advantage of it is even better. The X-Bionic Energizer Summerlight distributes the sweat precisely where it belongs - namely, over a wide surface and directly on the skin. The body's cooling is optimised, the athlete needs less energy for temperature regulation, and performance ability increases. If there is no sweat being produced, the action changes. Insulating air is stored and the systems serves to warm. Lighter than its big brother, the Bionic Energizer™, it still offers the same technology: Cools when you sweat, and warms when you freeze.