ColdGear Reactor adapts to your activity level for the right breathability & warmth for what you're doing. Lightweight, low-profile insulation embedded between two layers of performance fabric for the ultimate mix of warmth & breathability. Durable stretch-woven sleeves & back for mobility . Laser-perforated back neck for strategic ventilation . Secure zip hand pockets & chest pocket. Angled, half-elastic cuffs & drop back hem. Reflective logos.