The EMF-390 is by far the best tri-field detector on the market for the money. While most “EMF Detectors” only show you small bands of RF or just the magnetic field, the EMF-390 detects Radio Frequency Radiation (RFR), as well as Electric and Magnetic fields (EMF). The EMF-390 is perfect for detecting the dangers associated with WIFI, cell towers, electrical wiring, light bulbs, appliances and so much more. Most cell towers and EMF sources are hidden from public view these days, and so you won’t know if you’re in a “hot zone” unless you’ve got a tri-field (EMF AND RFR) detector. We strongly recommend GQ-390 for its versatility and affordability. This meter is affordably priced at $100 less than the competition and the reviews are tremendous.