By what method do lucid dream mask detect REM sleep?

I've seen lucid dream induction masks. They blink when you are experiencing REM sleep. How do they detect REM sleep?By what method do lucid dream mask detect REM sleep?
Quoting from


http://theluciddreammask.com/





'; inside the Dream Mask is a small computerized circuit panel and a sensitive infrared motion detector that can recognize when you enter REM (Rapid Eye Movement) sleep鈥攖he dream stage of sleep.


You see, when you鈥檙e looking at various objects within your dream, your eyes actually move even though you鈥檙e sleeping. And when the Dream Mask detects these eye鈥檚 movements, it will then flash a series of soft red LED lights.';





I can believe that, but then it goes on to say





';And when you begin to notice these soft red lights within your dream, you鈥檒l quickly realize that you鈥檙e dreaming!


And from that point on.. you鈥檒l be able to unlock the hidden secrets of your mind to unleash the power of your imagination to access your innermost desires and ambitions to expand your unique and hidden potential and step through opened doorways to inspiration, creativity, and enlightenment!';





Sorry, I cannot believe that, and neither should you. Still, if you want to order one, it's your money you are wasting, not mine.