Start with Primaloft insulation and put that on the core where you need massive wamrth. Then take our windproof softershell fabric and put that across the arms and shoulders where you take the brunt of the wind. What you get is a lightweight hybrid that layers easily under a shell and protects you from the cold off the hill. UA Storm gear uses a DWR finish to repel water without sacrificing breathability. 100g Primaloft insulation is lightweight, water-resistant, breathable, and can be compressed without losing warmth. ColdGear Infrared uses a soft, thermo-conductive inner coating to absorb and retain your own body heat. Windproof, bonded 2-layer softershell material on chest and arms. ColdGear cuffs add stretch and warmth that shuts out the chill. Chest media pocket with interior escape and secure hand pockets.