I'm not sure how well it will work if used in an emergency but my brother is a physician, and said it works. So take it as you will, a life is worth the price of the device if it could very well be beneficial to you. That being said, the reason I said it has a low value for the money is because they could sell it for a bit cheaper. It is less than a dollar to make, yet they charge what they do. I coughed it up out of necessity.