The meters are crap. My wife is our trainer and saw one go off when she walked by a computer, and she's been outside with it and seen BOLTS STRIKING THE GROUND and the thing didn't register. We just use the eyeballs. Once we see the flash we're off. Used to count the secs between bang flash, but now we're off with one strike. Also, last year we stayed out when the sky looked particularly bad, rain and thunder, but no lightning where we were. Apperehently, a tornado hit a HS about 8 miles from us. Glad too many parents didn't hear about that one.