1. It is easy to operate and move, convenient for on - site measurement, and can identify magnetic field sources and electric field sources. It is equipped with a built - in electromagnetic radiation sensor to make the test results more accurate. 2. It has an automatic sound and light alarm function. When the test value exceeds (40 volts per meter for the electric field, 0.4 Tesla or 4 milligauss for the magnetic field), the sound and light alarm of the electromotive force tester will be triggered. Press and hold the middle button to turn on/off the sound alarm. 3. It has a large - screen backlit liquid crystal display for easy reading. It is equipped with a rechargeable battery and has functions such as average value and reading, data retention, dual units, and temperature measurement. It will automatically shut down after 5 minutes of inactivity. 4. It can be used to test personal computers, laptops, TVs, mobile phones, ovens, refrigerators, telephones, WIFI routers, mobile phone signal towers, and household appliances, etc. 5. Electric field: - Measurement range: 1 volt per meter - 1999 volts per meter - Alarm value: 40 volts per meter - Resolution: 1 volt per meter 6. Magnetic field: - Measurement range: 0.01 Tesla - 99.99 Tesla / 0.1 milligauss - 999.99 milligauss - Alarm value: 0.4 Tesla / 4 milligauss - Resolution: 0.01 Tesla / 0.1 milligauss 7. Temperature: - Resolution: 0.1 (unit is missing in the original text) 8. Color: Black 9. Material: Plastic 10. Package contents: - 1 electromagnetic radiation tester Only the above package contents are included, and no other products are included. 11. Notes: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the actual one. The allowable measurement error is +/- 1 - 3 cm.