Made with the very same Japan-made Nanotechnology as NanoDri signature sweatproof apparel line, these button downs are very effective at blocking sweat stains all over the shirt, including the sides, back and underarms. Additionally featuring a silk touch non-stick sweat wicking interior and water proof membrane in the high friction area of the under arms, this shirt will have your back if you tend to sweat a lot but don't want others to know about it.