VLF stands for Incredibly Small Frequency and is the same engineering Employed in detectors built for cash, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz starting from three kHz to 70 kHz. Listed below are 5 reasons why you may opt for a VLF about a PI http://sarmacikrolewscy.phorum.pl/viewtopic.php?p=24851#24851