ColdGear Reactor intelligent insulation adapts to any activity for non-stop comfort & total versatility. Lofty insulation with a unique quilting pattern that traps heat, but still allows air to flow so you don't overheat. UA Storm technology repels water without sacrificing breathability. Smooth, ripstop woven body fabric is lightweight & extremely durable. Fleece side, lower sleeve & shaped back stretch panels offer extra breathability & mobility for zero distractions when you swing. Mock neck construction for added coverage & warmth. Shaped hem with drawcord adjust.