The Castelli Climber's 2.0 cycling jersey is made for warm days. The Castelli Climber's 2.0 cycling jersey is one of the most lightweight cycling jersey available. Not only cool in the summer, but also lightweight and with an aero fit. The Castelli Climber's 2.0 cycling jersey is a jersey for in the mountains. The Climber's 2.0 also proved to be astonishingly good in the wind tunnel tests. He scored only 2 watts more than the Castelli Aero Race 5.1, which saves about 12 watts on an average cycling shirt. So you don't have to choose between a fast or breathable shirt anymore, with the Castelli Climber's 2.0 jersey you can add an absolute top to your cycling clothes!