WARMTH WITHOUT THE WEIGHT FOR COLD ROUTES. The Nike AeroLayer Jacket is designed to trap warm air for super lightweight warmth. It is water-resistant and breathable so you can tackle your mileage regardless of the weather. Water-Resistant and Breathable Nike AeroLayer technology utilizes a layer of lightweight insulation between a water-resistant shell and inner lining to provide warmth and breathability. Lightweight Warmth Fill throughout has details between the fill that trap warm air. The result is warmth without weight. Stretchy Freedom Stretch fabric on the side panels and under the arms lets you move freely. Ripstop woven fabric is durable and lightweight. Zippered hand pockets store small essentials. A flap conceals the zipper.