Phase Change Cooling Vests contain 6 oz. flame resistant treated cotton. Soft to the touch. Lightweight, cool and comfortable. Flame resistant through 50 washes. Adjustable mid section & shoulders with hook & loop strap. Cools for 2-3 hours, set at 65°. Includes 1 pair cooling packs. Weighs 6.5lbs. Vest length 20.5”. Dangers of Heat Stress video