VLF means Extremely Small Frequency and is similar technologies Utilized in detectors developed for coins, jewellery, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from 3 kHz to 70 kHz. Here i will discuss five reasons why you might opt for a VLF more than a PI http://gzew.phorum.pl/viewtopic.php?p=607435#607435