BLACKHAWK! Products Group's Warrior Wear Thermostatic Base-Layer garments Engineered Fit series are designed to regulate body temperature, wick out moisture, inhibit and control the growth of odor causing bacteria, and provide the wearer with total freedom of movement with maximum comfort. The Engineered Fit series uses material technology that allows the wearer to choose between a body-contoured Standard Fit and a full Compression Fit simply by size selection. To achieve a Compression Fit, or a true next-to-the-skin fit, select a size one down from your normal size. The Compression Fit eliminates any potential friction related “hotspots” and helps to reduce muscle fatigue.