Mission Enduracool Lockdown Reversible Cooling Headband Cools Instantly When Wet to 20 below average body temperature Wicks away sweat from the head and promotes moisture cirulation Chemical Free. Regulates evaporation to help cool UPF 50 Sun Protection To activate cooling technology: Get it soaked, wring out excess and snap three times. Typically, stays cool for up to 2 hours when wet. To reactivate, simply re-soak and re-snap.