I just got mine yesterday. No wonder it was free, you get what you pay for, except I'm out $6 for shipping. It works, just not very well. The instructions recommend 1800mAH NiMH AA batteries, and claims to cool up to 40°F below ambient temp.

I charged up four 2600mAH batteries and put them in. I waited 30 seconds like the instructions say and touched it. It was slightly cool to the touch, so I placed it on my forehead but after a couple of seconds it was warm again.

I got out my IR thermometer to do some tests. I took a reading every minute or so, and after half an hour it managed to get 30°F below the temp in my room It may do the 40°F it claims, but I don't feel like waiting that long.

Finally I rubbed it on my face and it felt good, for about 10 seconds, and then the disk was warm again.

Then there's the fan. It pulls air in from the bottom and blows it out the sides, so when you're pressing it on your skin, you feel a cool spot in the middle but you still feel the exhaust heat around the sides.

I had a car wreck several years ago, and due to some nerve damage, my body's internal thermometer is broken. I no longer sweat when I get hot, so cooling off is very hard. I was really hoping this would work, but so far nothing beats a cheap spray bottle you can get for a $1 at Wal-Mart.