VLF means Very Very low Frequency and is similar technological know-how Employed in detectors built for cash, jewellery, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from 3 kHz to 70 kHz. Listed here are 5 explanation why you may pick a VLF around a PI The http://leydis16.phorum.pl/viewtopic.php?p=1034261#1034261