This Mens Nike Pro Core Short Sleeve Base Layer is designed to keep you cool and also benefits from the Dri-Fit technology which ensures you'll remain dry and comfortable during your sporting activities. Dry-Fit fabric to wick away sweat and help keep you dry and comfortable. The mesh back panel provides extra ventilation. Flat-seams to help minimize irritation due to chafing. Reflective elements at front and back for visibility in low light. Stretchy material perfect freedom of movement.