Body mapped with thinner Microtech under the arms for flexibility and ventilation. Thicker Microtech in the body and arms to block wind. Great for the slopes or the frigid December turf. Worn for skiing, football, baseball, track, etc. Arctic Microtech shirt wicks moisture and blocks the wind. Designed to keep you warmer and more comfortable without the bulk. Anti-Microbial fabric to cut down smell and odor. Perfect for any sport or outdoor activity where you need to maintain heat between workouts. 100% MADE IN THE USA.