Castelli Women's Alpha 150 Jacket The Castelli Women's Alpha 150 Jacket is the 'no excuses' winter cycling jacket. Get out and ride no matter what. Twelve years of continual refinement have led to a winter jacket utilising the very best performance fabrics and innovative construction techniques that deal impressively with a wide range of conditions, both cold and wet. The power of Polartec®  It all starts with the Castelli exclusive 150g Polartec® AirCore™ electrospun air-permeable membrane - windproof, waterproof and yet incredibly breathable, this performance garment technology ensures rain doesn't get in while sweat can get out. Whether it's base miles or hitting VO2max intervals, it will keep you feeling fresh, dry and focused. Meanwhile, the inside features a Polartec® Alpha™ inner liner, which provides amazing warmth-to-weight. This powerful insulator also enhances moisture management, wicking away sweat before it can cause you to shiver.  Fit for efficiency Castelli has given the Alpha 150 a tailored fit, with the stretch fabric offering an energy-saving snug fit but allowing easy movement on the bike. No more bulky winter jackets to sap your watts here. Practical features you'll love include the easy-sliding YKK® Vislon® zipper that opens from the top and bottom - perfect for ventilation control. Rear pockets make it easy to carry your essentials, and reflective piping at the bottom makes you easier to see on those early starts and late finishes.  Ideal for cold, dry days, yet will keep you dry in all but the most driving rain, the Alpha 150 Jacket gets you outside and building your fitness base in all weathers, all while your peers are sheltering indoors.