Laser perforations allow air to circulate in the jacket, making the jacket ideal for intense workouts and races where every gram counts and a high degree of breathability is mandated. The elastic binding on the hood, the cuffs and at the hem give you perfect fit. Its own integrated stuff sack in the hood means the jacket can be packed up small in your running pant or shorts pocket or the belt of your pack. Reflectivity on the back and front of the jacket ensure you can be seen when running at twilight or at night.