+ 5 Degrees Warmer! Using the most advanced performance technology available, our proprietary fabric offers you the highest level of skin protection. The EIS shirts are proudly made in the USA. Our special fabric technology provides you with many outstanding performance features: *Health A+ Offering superior sun protection with the equivalent of UPF 50+ *Mega Heat Technology This self-heating technology is embedded in the fabric and heats your body temperature by 5 degrees. Your movement generates the heating effect and will keep you warm. *Nanoplex Microscopic nano particle attached to fabric fibers make these performance features long lasting. Not a fabric finish. *Easy Care Normal wash, quick drying, and no shrinkage. *Odor Control Our special wicking fabric helps control body odor.