This product stayed cold and refreshing for 3-4 hours.  I thought from other reviews that it would stay cold for much longer; I called the vendor and spoke with a helpful man who said in high humidity situations the bandanas would stay cold only for a few hours.  He offered to return my money if I was in any way dissatisified.  I had purchased them for our trip to Florida (in June) and knew that a few hours of cool wouldn't be a lot of help at Disney but decided to keep them anyway.  We did use them and they worked well for 3 hours or so in the 100 degree heat and high humidity. I bought three of them and if I rotated them in and out of the cooler I'm sure they would be helpful for 4 hours or so in normal summer heat.