[3-in-1 Function] This db meter has three functions: noise, temperature, and humidity. The noise level indicator can detect real-time data at any time, and three functions make you feel more at ease. [Efficient Charging] The noise decibel meter is powered by a built-in 2000mAh lithium-ion battery and comes with a 9.9-foot USB charging cable, and the plug is included in the package to save you time. At the same time, because the battery of this smart decibel meter has a large capacity, you don't need to charge it all the time. [High Accuracy] This noise meter is available in four levels: Quiet/Comfortable ( 60dB), Noisy (60-75dB), Loud (75-85dB) and Extremely Loud ( 85dB). Temperature range: -10C -50C (14F-122F) Humidity range: 20%-85%. [Simple Operation] This sound decibel meter is very simple to operate, just plug the USB port into the power adapter and the DC round head into the device under normal conditions. You can measure the current decibel level as well as the temperature and humidity in real time. [Wide Application] This noise monitor can be hung on the wall or placed on a tabletop. It can be applied in different scenarios, such as hospitals, classrooms, factories, homes and offices, etc. It gives you the level of sound in time, so you can turn it down or increase the volume in time.