Perfect for running Gore have developed N2S and it is now lighter and even more comfortable next to the skin. The fabric and fit now has much more in common with a long sleeve top for comfort but has the protective qualities of a jacket. N2S was invaluable in our running wardrobe last winter, with bitter wind chill from October right through to May if this winter is as cold you will certainly get your monies worth out of this top. Total wind block in an easy to wear garment. Love it!! This seasons styling is stunning. A medium equates to a size 12.