VLF means Extremely Reduced Frequency and is similar engineering Employed in detectors created for coins, jewelry, and relics. VLF detectors broadcast at frequencies calculated in kilohertz ranging from three kHz to 70 kHz. Listed below are 5 main reasons why you could possibly select a VLF around a PI Second, http://gzew.phorum.pl/viewtopic.php?p=623512#623512