VLF stands for Pretty Minimal Frequency and is similar technological know-how used in detectors crafted for coins, jewellery, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from three kHz to 70 kHz. Here are five main reasons why you may go with a VLF above a PI http://taniecirlandzki.phorum.pl/viewtopic.php?p=119213#119213