The Medical Medium calls radiation exposure one the "Unforgiving Four" when it comes to illness. After reading Dr. Mercola's book, EMF*D, on the dangers of wireless exposure, I decided to try and limit my family's EMF exposure as much as possible. When I asked Xfinity customer service how to turn off my wireless, I was never told about the 3rd signal that all of their modems contain. Had someone not told me about it, I would have believed that after turning off the 2 main wireless signals manually that I was free from radiation exposure. This is an example of why meters are a must for avoiding radiation exposure - you don't know what you don't know!