This is the jacket for going fast on those in-between days when it's too warm for a jacket and too cold for a jersey. Traditionally, you might have used a vest and arm warmers on a day like this, but this jacket does it better. Rather than blocking all the wind on the body, the stretch woven fabric lets a small amount of air through. It blocks enough air that you don't get cold but lets enough through to keep you drier. Working together with the outer fabric is Polartec® Alpha® insulation in key areas to nearly weightlessly add more warmth without reducing breathability. The jacket is cut close to body, making it our most aerodynamic jacket. Not that that you need aerodynamics in the winter, but we're firm believers in Fast Is Fun. The close fit also makes it warmer than the minimalist fabrics would normally allow. Other features are strictly rider focused: The easy-sliding YKK® Vislon® zipper makes one-hand ventilation simple. Three rear pockets have plenty of room for whatever you need on long rides. It's cut short to not bunch up in the front or back. Reflective details help you be seen. The fabric is water repellent to keep splashes and brief showers at bay.