The Misty Mate is sort of like a personal water mister (no electric fan involved). If you've been to an amusement park in the summer and seen those "cooling stations" where they have a fine mist of water spraying, it's sort of like that.
You have an insulated canister that you fill with water and you can even add ice. Once the container is sealed, you pump it up to pressurize it, like those water gun toys kids play with in the summer.
The canister is then strapped around your waist or carried on your back. There's a short hose with a nozzle on the end. When you feel hot, you just aim the hose at yourself and hit the release button. You get a fine mist of cool water sprayed on you.
I liked the idea that it has no electrical parts and therefore no batteries. You also do not need to keep pulling a trigger to pump the water like you do with those water fans. You pump it up when you add the water and it should last until you need a refill.