Ergodyne - EGO12303 Remaining hydrated for up to 4 hours, this Evaporative Cooling Bandana helps maintain a healthy body temperature at work. Use in construction, landscaping, assembly, iron/steel fabrication and more. Activated polymers bring cooling power where you need it most. Activate by soaking in water for 2 to 5 minutes. Tie bandana is reusable. Simply soak in water to reactivate. The tie closure means you don't have worry about the fit. Stars and Stripes design shows your patriotism.