Craig,

Long, low exposure isn't anywhere near as bad as short, high exposure. You are exposed to low level exposure every day of your life (doesn't get much longer than that). It's called background radiation. We humans have adapted to it.

These little gizmos have a cool gadget factor, but for actual use in an emergency they aren't going to tell you much useful information, and you would have to know how to interpret the information that it does give you.

As a radiation physicist, I teach classes on radiation detectors, and you can probably make a more useful detector at home out of spare parts than these things are. Even the old civil defense detectors are probably better than this thing is. And the claim that they detect fast neutrons borders on fraud.

Save your money folks...

Greg