Though I was surprised that these aren't the basic square shape that I picture when I think "bandana," these little things WORK! They are more of a tubular shape, with the polymer beads in a sewn-in pocket in the middle of the bandana. We tried soaking for thirty minutes, but there was no word of "over soaking" them, so we tested them out after soaking for as long as an hour and as little as twenty minutes. Either way it does work, cooling the squishy beads which can be quite refreshing on a hot day. It took about two full days to (mostly) dry the hour-soaked bandana, and it was still cool. Very helpful for hot weather.