X-BIONIC Energy Accumulator is the first genuinely hi-tech underwear. It works to maintain body temperature at an optimum 37 degrees, cooling you down when you sweat and keeping you warm when you're cold. Its clever regulation system works with the most reliable of starters: your sweat. Inspired by nature, created by scientists, tested by endurance athletes, X-BIONIC fits like a second skin and incorporates features designed to meet the entire range of sport-specific demands. Winner of more than 300 international awards.