VLF stands for Quite Low Frequency and is the same engineering used in detectors created for coins, jewelry, and relics. VLF detectors broadcast at frequencies calculated in kilohertz starting from 3 kHz to 70 kHz. Here i will discuss 5 main reasons why you could possibly choose a VLF in http://gzew.phorum.pl/viewtopic.php?p=614350#614350