VLF stands for Incredibly Small Frequency and is similar know-how Employed in detectors developed for coins, jewellery, and relics. VLF detectors broadcast at frequencies calculated in kilohertz starting from 3 kHz to 70 kHz. Here are 5 explanation why you may select a VLF around a PI As a result, http://nec.phorum.pl/viewtopic.php?p=763286#763286