My husband works with REAL EMF emitters due to his job: Tower operations. He has to wear a high tech meter which is much like a voltmeter. You wouldn’t use your phone to test if there was a live wire in your house to not electrocute yourself while installing a new outlet or light switch because 1) it’s impossible 2) not it’s purpose. This is a novelty app, a toy, and so I’ll give it a better than 1 star rating for functionality of EMFFieldDetectorRFScanner , not its intention just development function, it works and doesn’t crash. But as for what it claims it does, it does not. Don’t pay for this. Play with it, test it, but remember it’s a toy. If you did spend money, I am sorry, it’s akin to paying for your coffee three times: first when you buy it, second when you tip too high for it. Your phone can not detect EMF. Period. A brand new magnet, out the package not near or having ever touched an electrical device emitted very high. A second magnet, same. My clock: nothing. My Fitbit: nothing. My stove: Nothing! A fridge magnet, omg dangerous. A flat quarter sized magnet for my clipboard: dangerously high. And only when I touch it to the phone. If you want a real monitor if you are truly concerned about EMF and your health, please do yourself a favor and put your money towards a real meter. Otherwise understand that EMFFieldDetectorRFScanner and apps like this are a novelty item, a toy.