VLF means Really Very low Frequency and is similar technological innovation Employed in detectors designed for coins, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from 3 kHz to 70 kHz. Here are 5 explanations why you might choose a VLF around a PI Together with http://classichonda.phorum.pl/viewtopic.php?p=173497#173497