ColdGear® Reactor insulation adapts to your activity level for the right breathability & warmth|Knit fabric on sleeves, side & back panels has soft, brushed "nodes" for the right warmth that breathes|Smooth, ripstop woven front body fabric is lightweight & extremely durable|4-way stretch material moves better in every direction|Material wicks sweat & dries really fast|Shaped hem for enhanced coverage|Reflective details for greater visibility on low-light runs|Built-in interior thumbholes are more comfortable, keep sleeves secure & help seal in your body heat