VLF means Incredibly Lower Frequency and is similar technological innovation used in detectors developed for cash, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from 3 kHz to 70 kHz. Here i will discuss five explanations why you may select a VLF more than a PI http://forum.446.s1.nabble.com/How-to-Choose-Metal-and-Gold-Detectors-td140733.html