Lots of people wonder - "How do you tell if your phone is emitting EMF?"
The answer is easy - watch the phone battery. If your phone drains battery 2x as fast as normal in a purported Faraday cage - you have a lemon.
Why? Because the phone drains battery fastest when it is constantly searching for signal. It searches when it GETS signal - implying the bag is not working 100% - enough to stop a reliable connection, but not enough to stop all signals - giving the phone "false hope" that causes it to drain the battery by upping the signal strength.
I recently put an iPhone inside one of my blocker sets to test this. Over the course of 20 hours, the battery dropped...15%. For an iPhone, that's as low of a battery drain as you can get - the phone didn't even try to connect to the outside because it was hopeless.
I depleted the battery 50% in one hour of cell phone testing where the phone was constantly searching for signal.
This has interesting implications. If your phone is burning the battery trying to get a signal - it is emitting far more EMF than normal. So even if you have a weak Faraday shield, you might well be receiving more EMF that you would WITHOUT the shield!!!
The only way to be sure you are reducing EMF is to have a Faraday cage bag that reliably leads to "no service" AND doesn't drain the battery.