VLF stands for Incredibly Small Frequency and is similar engineering used in detectors built for coins, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from 3 kHz to 70 kHz. Here's five reasons why you would possibly decide on a VLF more than a PI Make http://family.bigbrother.bg/forum/topic_show.pl?tid=238941;msg=NewPost;sid=62e34f56b6afecc56963bb66c221054b