Under Armour's famous ColdGear base layers are designed to keep you warm, dry, and light. This fitted shirt is made from quick-drying, 4-way stretch, 7-oz. 93% polyester, 7% elastane. Heavy-weight Base 3.0 layers offer max warmth for "extreme" cold conditions and low activity levels. 1/4-zip neckline provides on-demand ventilation. Ergonomically placed flatlock stitched seams and raglan constructed shoulders offer ultimate mobility and comfort next to your skin. ArmourBlock anti-odor technology helps reduce unpleasant body odor.