VLF means Pretty Lower Frequency and is the same know-how Employed in detectors designed for coins, jewelry, and relics. VLF detectors broadcast at frequencies calculated in kilohertz starting from 3 kHz to 70 kHz. Allow me to share 5 explanation why you might pick a VLF more than a PI http://inquisnower.phorum.pl/viewtopic.php?p=750259#750259