Does not work
within a week or so it completely stopped working. I hold down the button and it shows a solid red, meaning high alcohol concentration, even though no one is blowing into it.

Good for only a few tries
I got this device to test myself before I drove after drinking, like every other paranoid driver. It worked like a charm for about a month of two, then it ceased to calibrate when turned on, and stayed on the red <.08bac forever. So basically it became worthkess after a short while. But for fifteen bucks, what do you expect?

Great for the price
This was a great stocking stuffer and lots of fun throughout the Christmas party. We didn't have anything to calibrate the results so I'm not sure how accurate it is - but it seemed reasonable. Hopefully it will be a gentle reminder not to drive after drinking.

One note - don't take a big gulp of alcohol and immediately test yourself. You'll show as highly intoxicated even after just one drink. Wait a few seconds - that seemed to produce more reasonable results.

Inexpensive, but didn't last very long.
This tester seemed to work OK at first, but only lasted for about a week. Now it seems to have lost calibration and is basically useless. Save your money and buy a better unit!

It works
I would not trust any device, as far as drinking and driving. However this little tester really does work. I drank one Vodka drink and the tester gave me a yellow light. Red is the next level up.

I tried everything i.e. brushing my teeth, eating candy, even drinking milk. No fooling this tester. The light remained yellow.

Best advice don't drink and drive! duh! I don't think the CHP would let you off the hook, if you told he or she that your tester said it was ok to drive.