Precise Measurement: Built-in electromagnetic radiation sensor. After processing by the control microchip, the radiation value can be displayed on the clear LCD digital display. The radiation unit of the test magnetic field can be mG/T, and the unit of the electric field is V/m. [Tri-level value]: Use the three-color light to quickly identify and remind you whether the current radiation level is safe. Safe (0-1.99 mg/0-0.19 ut), Caution (2-3.99 mg/0.2-0.39 ut), Hazardous (greater than 4 mg/0.4 ut). When you are in danger, the alarm will sound. Multifunction: Test the average or maximum readings and save the data display with one button. The large backlit LCD display is crisp and clear. Auto power off after 5 minutes of inactivity. Wide range of applications: The measurement frequency can reach 5Hz to 3500MHz. Mainly used for testing TV, computer, printer, microwave oven, refrigerator, low frequency equipment, etc. Please note: This device is powered by 3 AAA batteries, which are not included. You need to buy it yourself.