Castelli's Alpha Wind Jersey FZ takes on the coldest weather you can pedal through with lightweight, double-layer wind and rain protection. A Windstopper 150 outer layer blocks wintry breezes and damp weather, while the Prosecco Stratus liner offers a thermal mid-layer with its own front zip. The two layers allow for more graduated temperature regulation and venting. The Nano Warm back vents well for even more temperature regulation. This hi-tech jersey feels pro too, thanks to the advanced patterning for a close-to-body fit. With a raw-edge waist, it lies flat and moves with you, ensuring the Alpha's always where it should be, and the silicone text gripper keeps the jersey from riding up. It's topped off with an articulated collar and three rear pockets with an extra zippered pocket.