The outer jacket is made from 150g Polartec® AirCoreTM, an exclusive Castelli fabric that is windproof and water repellent, while also being air permeable and breathable, with enough stretch to ensure a comfortable fit. All but the heaviest showers will be fended off.The insulation is Polartec Alpha, which is warm but allows moisture to escape. This inner, as with all models of the Alpha jacket, is stitched into the back of the jacket but left as a separate layer at the front.A second zip gives riders the choice to opt for weather proofing and warmth, just weather proofing or just warmth, or neither, depending on their preferences and the conditions, by zipping both layers or leaving one, the other or both unzipped. This jacket therefore ensures the rider's comfort in the widest possible range of conditions, including the cold and wet.The jacket offers a close, tailored fit without too much bulk, giving the feel of a winter jacket in cold or freezing conditions, without ever being too