Easy to operate and move, convenient for on-site measurement, and effective identification of magnetic field source and electric field source. Equipped with high-quality built-in electromagnetic radiation sensor, making the test results more accurate. Automatic audible and visual alarm. When the test exceeds (electric field 40 V/m, magnetic field 0.4 or 4 mG), the audible and visual alarm of the electromotive force tester will be triggered. Press and hold the middle button to turn the audible alarm on/off. Backlit LCD for easy reading, rechargeable batteries, average and peak reading, data retention, two-cell display, and temperature measurement. Power off automatically after 5 minutes without operation. Can be used to test PC, laptop, TV, mobile phone, oven, refrigerator, telephone, Wi-Fi router, mobile phone tower, and household appliances. Electric field: Range: 1 V/m - 1999 V/m Alarm: 40 V/m Resolution: 1 V/m Magnetic field: Range: 0.01 T - 99.99 T / 0.1 mG - 999.99 mG Alarm: 0.4 T / 4 mG Resolution: 0.01 T / 0.1 mG Temperature: Resolution: 0.1 Color: Black Material: Plastic Package Contents: 1 x EMF Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item to be slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.