VLF means Pretty Minimal Frequency and is identical technological innovation Employed in detectors constructed for coins, jewelry, and relics. VLF detectors broadcast at frequencies calculated in kilohertz ranging from 3 kHz to 70 kHz. Here's 5 reasons why you would possibly choose a VLF around a PI The GPZ 7000 https://utreediff.com/forum/viewtopic.php?t=1317