The device uses broadband pass technology, making it sensitive in detecting electromagnetic fields. It features 5 LED color signals to indicate different levels of magnetic field strength. Suitable for indoor or outdoor use when measuring electric devices or power lines. Measures a wide spectrum of EMF from 50 to 20,000 Hertz. Designed for identifying areas with elevated electromagnetic field levels. Simple and user-friendly design. Lightweight for easy handling. 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) LED indicators: 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 (20+ mG) Operating temperature: -18 to 49°C (0 to 120°F) Power source: 9V battery Weight: 170g Color: Black Material: ABS, Electronic components Dimensions: 14.6 x 5.8 x 25.5 cm Package Contents: 1 x K-II Electromagnetic Field Meter 1 x Instruction Manual Note: Light and screen differences may cause slight variations in the color appearance. Measurement error is +/- 1-3 cm.