The Under Armour Women's ColdGear Reactor Vest is a top-rated sleeveless safety convertible packable activewear vest that offers exceptional warmth and comfort. It is made from a blend of polyester and elastane, providing both insulation and stretch. The vest features ColdGear Reactor insulation, which adapts to your activity level for the right breathability and warmth. It also has zippered hand pockets and an internal chest pocket for secure storage. The vest is convertible, allowing you to pack it into its own pocket for easy transport. With its innovative technology and reliable performance, the Under Armour Women's ColdGear Reactor Vest is highly recommended by customers.