K2 EMF Meter & 822a-bl EMF w/ Backlight K2 EMF Detects ELF range (50 to 1,000 Hz) & VLF range (1,000 to 20,000 Hz) Accuracy of 5% at 50-60 Hz 822A-BL great for investigations in the dark with the back light to make the screen visible in the dark. 822 Digital Measurement Range: 0.1 mGauss to 199.9 milliGauss Accuracy: 4% at 50-60 Hz