It's the lightweight jacket you can actually work out in. That's because the insulation adapts to your activity level, so as you heat up, it lets out warmth. Fitted: Next-to-skin without the squeeze ColdGear® Reactor intelligent insulation adapts to any activity for non-stop comfort & total versatility Lofty insulation with quilting that traps heat, but still allows air to flow so you don't overheat UA Storm technology repels water without sacrificing breathability Smooth, stretch-woven body fabric is lightweight & durable Brushed panels offer extra breathability & warmth Generous, 3-panel hood construction with bungee adjust Shaped cuffs for added coverage & protection Secure, zip hand pockets 90% Polyester/10% Elastane