Usage Tips:The use of broadband pass technology within device which means being more sensitive than other EMF meters in picking up electromagnetic frequency. There are 5 colour LED signals to different level of magnetic field. It is suitable to use either indoor or outdoor applications for measuring any electric device, power line Measure wide spectrum of EMF from 50 to 20,000 Hertz Identify potentially harmful long term overexposure to EMF Sensitive in detecting electromagnetic field. Simple & user friendly device. Light weight Specifications Detection range: 0 to 20+ milliGauss (mG) Detection frequency: 50 / 60 Hertz (50 to 1,000 Hz - ELF; 1,000 to 20,000 Hz - VLF) Accuracy: +/-5% (Typical) 5 LED signals for different level of magnetic field: Green (1) - Normal magnetic field (0 - 1.5 mG) Green (2) - Low level magnetic field (1.5 - 2.5 mG) Yellow - Mid level magnetic field (2.5 - 10 mG) Orange - High level magnetic field (10 - 20 mG) Red - Extreme high level magnetic field ( 20mG) Operating temperature: -18 to 49Celsius (0 to 120Fahrenheit) Power source: 9V battery Weight: 170g colour: black Material: ABS, Electronic component size: 14.6*5.8*25.5cm Package Contents: 1* K-II Electromagnetic Flowmeter 1* Instruction Manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.