I run 5-6 marathons and several halfs each year. Hot summer days call for a sleeveless top. The material in this top is soft, the result of fine thread and a tight weave. (This may be due to using re-cycled poly.) All my older tops have larger thread and open weave - allowing better air circulation and better wicking properties; thereby providing a cooler run. The shipping cost makes it not worth sending back, but I would not buy another.