Knocking out a long, uninterrupted climb always sounds like a good idea from the air-conditioned comfort of home, but we always forget how punishing a climb can be when the weather's hot and the grade is steep. While we forget how much the last climb hurt, Castelli has a better memory, so it designed the Climber's Women's Jersey to keep the heat turned down when the summer temps are up. Castelli employs 3D fabric architecture throughout its line, and the Climber features Flusso 3D on the front and shoulders and Strada Pro 3D on the back. Flusso is so light that you'll hardly notice it, and Strada Pro is hyper-efficient but has a little more structure to support the three pockets on the back of the jersey. Both wick moisture and breathe exceptionally well to keep you cool and dry. Castelli also engineers the Climber with a built-in bustier lining for comfortable support. AirMesh armbands keep your sleeves in place and provide an aerodynamic fit, and the 3/4-length zipper reduces bulk for an uninterrupted, smooth surface over the jersey's stomach.