When Castelli created this jersey they primarily focused on making it light for the big alpine climbs as well as cool for hot days. A real Tour de France jersey if there ever was one. But they didn’t want to completely ignore aerodynamics, so they used patterning similar to the Aero Race 5.1 Jersey, which they knew was fast. The resulting jersey is extremely cool and light and instantly became a favorite with pro riders. The surprise was when they put it in the wind tunnel. This lightweight jersey posted aero drag values just 2 watts slower than the Aero Race 5.1 jersey. Next time they ask you if you want aero or light, just answer, “Yes, please.”