It's like a climber winning the green jersey. 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 Castelli didn't want to completely ignore aerodynamics, so they used patterning similar to their Aero Race 5.1 Jersey, which they knew was fast. The resulting jersey is extremely cool and light and instantly became a favorite with their pro riders. The surprise was when they put it in the wind tunnel. This lightweight jersey posted the same results as the Aero Race 5.0 Jersey, just 2 watts slower than the updated 2016 Aero Race 5.1 Jersey, the most aero jersey Castelli has ever tested. Next time they ask you if you want aero or light, just answer, " Yes, please."