I have a device also, and the most worrisome
equipment, according to the manual, is magnets. I live within walking distance of one of the biggest hydroelectrical Dams in the world, and as long as I do not go on a tour of the Dam, I get along fine. Otherwise, my device could be rendered useless, or it could cause the device to fire for no reason.
Also, cell phones are not supposed to be within 12 inches of the device, or the same effect as above may occur.