The Under Armour Women's ColdGear Reactor Vest is designed to keep you warm and comfortable during your outdoor workouts. It features ColdGear Reactor insulation, which adapts to your activity level to provide the right amount of warmth. The vest is made from lightweight and breathable fabric, allowing for unrestricted movement. It has a high-visibility color and reflective details for added safety during low-light conditions. The sleeveless design and packable nature make it a versatile activewear vest that can be easily layered or worn on its own.