Provides immediate and long lasting cooling. Up to 3 days of cooling ability. Activate with 13-20 oz water. Lightweight, durable and machine washable. Easy to use, watertight filling cap. Lightweight, durable material ensures a comfortable fit all day. Vest features hi-visibility fabric, YKK zippers, and mesh panels for additional comfort and stretch. Patented dry evaporative cooling technology activates easily with water. No refrigeration, gels, or chemicals required. Capacity to cool up to 15° below ambient air temperatures. Moisture management. Machine washable.