The X-Bionic® Trekking Polo Shirt is a new generation of trekking wear. Because of the highly elastic knit construction the shirt fits perfectly and allows an optimal moving space. The unique mix of materials distributes perspiration onto the skin. The highly efficient evaporation capability of the textile keeps the body at its most effective performance temperature of 37° even at high physical activity. The patent pending 3D knitted shoulder and hip pads distribute the pressure of the rucksack belts and ensure aeration at these sweat intensive zones. The 3D-BionicSphere-System at chest and back cools when you sweat and warms when you freeze.