VLF means Extremely Low Frequency and is identical technological innovation Utilized in detectors constructed for coins, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from three kHz to 70 kHz. Here's 5 explanations why you could possibly choose a VLF about a PI One more challenge http://gzew.phorum.pl/viewtopic.php?p=623507#623507