Last summer my vehicle did not have air conditioning (it still doesn't, but last summer it didn't either). I received a misty mate from my deceased aunt's possessions.
It is very easy to operate, you fill it with water, use the pump attached to the bottle to increase the pressure inside the cylinder, then when you want refreshing mist sprayed over your heated sweaty skin, just point the wand at the spot you want to cool, and turn on the nozzle to release a refreshingly atomized spritz of cool water. it works on the evaporative cooling principle; the small droplets of water evaporates on your hot skin, taking the heat away with it, and it works really well. In fact, the same type of colling system is used for personal cooling by U.S. soldiers in desert climates, (like Iraq).
I got by the entire summer with a misty mate, and it wasn't exclusive to a vehicle. It was made to travel, with an insulated carrying puch and shoulder strap. I brought it too all the barbeque's and birthday parties, keeping myself nice and cool.
Now I must comment on the customer service. Trying to "upgrade" my misty mate, I broke an essential piece that kept it airtight, therefore allowing it to be pressurized. I called the company, and they said the part could not be successfully replaced because of the pressure needed to apply it, and therefore sent me a brand new misty mate. Even after I had told them I broke it, and I hadn't even purchased it. They made me happy, and gained a loyal customer (if I ever have to buy one that is).