Trekmates® Cooling crystal headwear contain polymer crystals that are stitched into the front headband of the hat. Once submerged in water (approx 4 minutes) the crystals will absorb and retain the water keeping the wearer cool for several days before they dry and slowly return to their original state, ready to be re-submerged. For extended cooling effect they can be refrigerated or placed in the freezer. To activate the crystals quickly run them under warm water first and when fully activated run in cold water.
This is an old style and Cooling Crystals may not perform.