The cooling cap isn’t quite as mad as it looks. To use, you place it under a running tap and it will absorb some of the water, then when you wear it the water will slowly evaporate thus cooling your head (and hopefully not just dripping down the back of your neck). Or in more technical terms:

The Hydroweave system combines hydrophilic (water-attracting) and hydrophobic (water-rejecting) fibers in a three-layer fabric that conducts body heat upwards, while retaining the cool water and releasing it slowly through evaporation; even while the middle layer holds onto water, your head remains cool and dry thanks to an inner lining that water cant permeate. The end resu lt is a hat that actually cools you more effectively the hotter the air temperature.

The Insulated Evaporative Cooling Cap is for sale at Hammacher for $24.95.