We made this jersey specifically to help win a tour de france by keeping the pro riders as cool as possible when the temperature climbs the semi open mesh fabric allows maximum airflow and the low lycra content helps maximize evaporative cooling the light airy feel has us reaching for this jersey from 25 and up should be used without a base layer for best effect upf 10 rating means that it filters out 90 of damaging uv rays features diablo mesh fabric for climbing the hottest mountain