Do you want to test the sound level? Do you need to know the noise level? Try our digital Sound Level Meter Tester . With this sound level meter you can measure the noise level in different areas, e.g. Such as home, school, factory, office, music room, shopping mall, etc. Noise Meter Wall Mounted Characteristics: 9.5"" Super large full screen LCD with large bold red font for easy reading. 24 hour real-time sound level monitoring. Support wall hanging (recommended) or free standing on desk.the product operation is very convenient, it can be used only by connecting the power supply (additional power supply needs 5V 1A) . Suitable for checking and monitoring sound level for home, family, business, study, industry, audio, air-conditioning refrigerators, etc. Specifications: Material: ABS Measuring range: 30 130dBA, 35 130dBC Frequency Response: 31.5Hz 8.5KHz Accuracy: 1.5 dB (see sound calibration frequency, 94 dB at 1 kHz) Frequency weighting: A or C weighting Digital display: 3 large LED digital display Resolution: 0.1dB100dB Display mode: fast and slow selectable Microphone type: Dia. 6mm ECM type Alarm Mode: Built-in alarm buzzer Operating voltage: USB DC5V 1A Operating temperature and humidity: 0 40 , 10% 80% relative humidity Storage temperature and humidity: 0 60 , 10% 70% RH Power supply: 5V 1A AC/DC adapter Item Size: 221 * 130 * 28mm / 8.70 * 5.1 * 1.1in Item Weight: 453g Package list: 1 * Sound Level Meter with Alarm1 * USB cable1 * connector1 * User Manual (English). 1. Hook up. 2. USB power socket. 3. Alarm switch indicator light. 4. Condenser microphone sensor. 5. Three 3.0-inch digital tube displays are used to display the noise value. 6. One-quarter copper nut, the user can fix the instrument on the tripod through the copper nut. 7, 3.5 audio 2-section socket, output 2KHz signal when alarm, can drive external speakers. 8. Calibration knob, reserved by the manufacturer. The instrument has been calibrated at the factory, please do not adjust it. 9. Button 1. Power switch key: short press to turn on, long press to turn off, 2. Down key: set to yes, short press to decrease the setting value, long press to adjust continuously. 3. Up key: set yes, short press to increase the setting value, long press to continuously adjust. 4. Alarm switch setting key: short press to set the alarm switch, long press to enter the setting. Set Alarm Short press (alarm switch setting key) to select the alarm switch. Each time the instrument is turned on, the default alarm is turned on, short press the alarm button once, the alarm is turned off, and the red light is off, and then short press the alarm button again, the alarm is turned on, and the red light is on. Long press (alarm switch setting key), the screen displays the alarm value, and the red indicator light of the alarm flashes. After power on, the default alarm value is 130dB. Press the up key or the down key to adjust the alarm value. Long press the up key and down key to continuously adjust, short press (alarm switch setting key) to save the alarm value, short press (power switch key) to exit the setting. Note: In order to prevent users from misoperation, the alarm value will be reset to 130dB every time the machine is turned on. When using the Sound Level Meter Tester , please pay attention to whether there is any blockage of foreign matter. If LCD display appears The numbers on the screen do not jump, and garbled characters appear. You need to restart the machine.