VLF means Really Very low Frequency and is similar technological know-how Employed in detectors crafted for cash, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from 3 kHz to 70 kHz. Here are 5 explanation why you might go with a VLF above a PI The https://utreediff.com/forum/viewtopic.php?t=1316