Eco Dynacool fabric Mesh inserts Reflective details for extra visibility Green-R: Sustainable Production Stay comfortable on every run with the Core Hard Running T-shirt. This T-shirt is made of thin Eco Dynacool fabric, which provides good ventilation and stays nice and cool. Smart mesh inserts further enhance air circulation to keep your body at an optimal temperature. Reflective details have been added to this running top, providing extra visibility in the dark or at dusk, so you can run with confidence any time of day