"What Our Gearhead® Experts Are Saying:""I've been wearing the AirExchange Short-Sleeve Shirt on everything from full-day summer hikes to casual Friday at the office and it handles both without missing a step. The perforated fabric is genuinely different from a standard polyester shirt, you can actually feel the airflow when you're moving, and the flat-felled seams mean a full pack never creates any hot spots or irritation.""Hot days call for a shirt that works as hard at keeping you cool as you're working at everything else, and the AirExchange Short-Sleeve Shirt from Marmot was designed for exactly that equation. The AirExchange perforated recycled polyester fabric is built around micro holes that enhance airflow and wick sweat simultaneously, keeping you dry and comfortable from the trailhead to the dinner reservation. Flat-felled seams add durability and eliminate pressure points under a loaded pack, a drop-in chest pocket handles the small items that need to stay close, and a straight hem keeps the whole shirt looking sharp no matter how long the day runs."