VLF means Very Very low Frequency and is similar technology Utilized in detectors built for cash, jewelry, and relics. VLF detectors broadcast at frequencies calculated in kilohertz ranging from three kHz to 70 kHz. Listed below are five reasons why you could possibly go with a VLF over a PI http://eurotrucksimulator.phorum.pl/viewtopic.php?p=1529480#1529480