Chill-Its 6668 Hi-Vis Safety Cooling Vest provides hours of core-cooling relief. Polymer-embedded cooling technology quickly activates for up to 4 hours of relief from the heat. Three layers include an ANSI/ISEA 107 Type R, Class 2 high-visibility shell, polymer-embedded mid-layer and a water-repellent liner to help keep wearers dry. Soak in water for 2 to 5 minutes to activate. Breathable mesh along the bottom of the light vest reduces weight, enhances airflow and prevents excess water from dripping onto clothing. Loops along the interior of the neckline allow you to insert cooling towels for additional cooling relief along the neck. Vest also features two lower interior pockets, an exterior pocket for storage and zippered closure for easy on/off. Large size fits chests up to 55" in diameter and offers a 26-1/2" long center back.