Compression garments seem to be all the rage in todays athletic world. Thats great for todays athletes, but todays operators and law enforcement officers need something different. Our Muscle Mapping shirts are designed to be worn under body armor and to provide support for an 8, 10, 12 or more hour workday. The 5.11 Muscle Mapping shirt features three distinct zones of compression to achieve this goal. Key design features of this shirt are the saddle shoulder construction that allows greater range of motion, yet prevents bunching, an underarm mesh panel that allows moisture to vent and evaporate easily, and flat-lock seams that reduce friction in order to prevent chaffing. Muscle Mapping is made out of Dri-X-treme® moisture-wicking, anti-microbial and quick drying fabric. 88% Tactel® nylon, 7% nylon and 5% spandex. Imported.