VLF stands for Pretty Reduced Frequency and is similar technologies Employed in detectors created for cash, jewellery, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from three kHz to 70 kHz. Here's five main reasons why you could go with a VLF in excess of a PI http://classichonda.phorum.pl/viewtopic.php?p=173503#173503