Light weight breathable, running windbreaker.

It may look like a windbreaker, but fewer jackets are more lightweight or more breathable than this ingenious layer. What makes it smart? We dotted the upper back with ventilation pores to allow heat to escape as your workout heats up. cinch down the hem, and pull the cuffs over your thumbs to get going on a chilly day. As your body temperature rises, you can open the hem, lower the zipper, pull up the cuffs. You’ll instantly start shedding heat without ever having to shed a layer. But if you do need to shed a layer, go for it. This jacket packs down small enough for the tiniest pack.