8820 Four-in-One Multi-Function Environment Tester Is an Instrument Integrating Noise, Luminosity, Humidity and Temperature. It Can Be Used in Industry and Civil Use to Detect Corresponding High-Fidelity Devices. The Noise Function Can Be Applied to the Noise Monitoring of Household Appliances and Environmental Construction; the Luminosity Function Is Used to Test Whether There Is Sufficient Brightness in the Lighting Field and Whether the Sensing Performance of Light Is Stable, Etc. The Tempera