*Notes on specifications: This page is a footnote link in all "Steve's Reviews" - metal detector and gold prospecting equipment reviews by Steve Herschbach. Two basic technologies are described here; Induction Balance (IB) and Pulse Induction (PI). Induction balance is often referred to as VLF, or very low frequency. This is a misnomer, as some gold nugget detectors and some coin detectors are not very low frequency units as normally defined. VF = Voice Frequency = 300 Hz - 3 kHz, VLF = Ver