The device uses broadband pass technology, making it sensitive in detecting electromagnetic fields. It features 5 LED signals to indicate different levels of magnetic field strength, suitable for indoor and outdoor use when measuring electrical devices and power lines. Measures a wide spectrum of EMF from 50 to 20,000 Hertz. Designed to detect electromagnetic field exposure with a detection range of 0 to 20+ milliGauss (mG). Detection frequency covers 50 / 60 Hz (50 to 1,000 Hz - ELF; 1,000 to 20,000 Hz - VLF). Accuracy is +/-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 includes: 1 x K-II Electromagnetic Field Meter 1 x Instruction Manual Note: - Slight color variation may occur due to lighting and monitor display differences. - Allow for a measurement tolerance of +/- 1-3 cm and weight variance of +/- 1-3g due to manual measurement.