VLF stands for Very Very low Frequency and is similar technologies used in detectors constructed for coins, jewellery, and relics. VLF detectors broadcast at frequencies calculated in kilohertz starting from three kHz to 70 kHz. Listed here are five explanation why you might decide on a VLF about a PI http://ostrza-avalon.phorum.pl/viewtopic.php?p=399658#399658