Fine workmanship and nice performance. Accurate and reliable with good durability. Operates on a single battery, reporting EMF measurements in five milli Gauss ranges. Measures wide spectrum of EMFs from 50Hz to 20,000Hz, and can register a cell phone within 2 feet. Helps measure electromagnetic fields to identify high-level emission appliances, beneficial for reducing radiation exposure. Easy-to-read multi-segment LED display, simple to use. Specifications: Material: ABS; Color: as shown; Accuracy: +/- 5%; Detection range: 0 to 20+ milli gauss; Detection frequency: 30~20,000Hz; Power supply: 1 * 9V battery (included); Item size: 140 * 52 * 25mm / 5.51 * 2.05 * 0.98in; Package size: 140 * 53 * 29mm / 5.51 * 2.09 * 1.14in; Package weight: 101g / 3.56ounces. Five Scales: 1st Light (Normal): 0-1.5 mG; 2nd Light (GREEN, Low Level): 1.5-2.5 mG; 3rd Light (YELLOW, Mid Level): 2.5-10 mG; 4th Light (ORANGE, High Level): 10-20 mG; 5th Light (RED, Extremely High): 20+ mG. Note: Due to different display and light effect, actual color may slightly differ from pictures. Please allow slight measuring deviation due to manual measurement. Package List: 1 * Detector, 1 * 9V Battery, 1 * English User Manual