VLF means Extremely Small Frequency and is similar technology Utilized in detectors developed for coins, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from three kHz to 70 kHz. Here's five reasons why you might choose a VLF in excess of a PI The GPX 6000 http://leydis16.phorum.pl/viewtopic.php?p=1026025#1026025