Castelli climbers 20 jersey full zipwhen castelli created the climbers 20 jersey they focused primarily on making it lightweight for big alpine climbs as well as cool for hot days on the road a real tour de france jersey if there ever was one aerodynamic cool and lightweightwithout completely ignoring aerodynamics castelli used patterning similar to the aero race 51 jersey which is the most aerodynamic jersey they have ever made the result is an extremely cool and lightweight jersey whi