Features: 1Maximum and Minimum Value Locking: The maximum and minimum value locking is a display function. After being enabled the maximum and minimum value measured from the opening time to the current measurement time (MAX: maximum value locking MIN: minimum value locking). 2Two Screen Display Modes: There are two screen display modes normal mode and night mode. The screen can be lit with one key in case of dim light. 3Film Keys: The film keys have better feel and longer life which can indirectly improve the working efficiency of the sound level meter itself. 4Hanger Back Clip : When your hands are occupied during work you can hang the digital sound level meter on your clothes or belt. 5Removable Wind Shield: When the measured value deviates it is convenient to calibrate and zero the noise sensor. 6One Click Switch to FAST and SLOW: FAST sensitive fast detection. SLOW more stable detection and more accurate data. 7One Key Value Locking: One key HOLD can lock the currently detected noise value providing you great using experience. Specification: Item Type: Digital Noise MeterProduct Material: ABSColor: As Pictures ShownWeight: Approx. 150g / 5.3ozAccuracy: 1.5dB (at the quasi reference sound pressure level 94dB at 1KHz )Frequency Response: 20Hz-8KHzDynamic Range: 50dBMeasuring Range: 30-130dBAFrequency Privilege: A RightDisplay Digits: 4 Digits Resolution 0.1dB Sampling Frequency Twice Per SecondLoad Indication: OVER and UNDER SymbolsDynamic Characteristics: FAST (Fast) and SLow (Slow) Reaction RatesMicrophone: 1/2 Inch Condenser MicrophoneOperating Temperature: 0-40 C 10-80% RH (Non Condensing)Battery: 3 AAA Battery (Shipped Without Battery)Product Size: Approx. 158x60x25mm / 6.2x2.4x1.0in (Without Hanger Back Clip)Application: It can be used for noise engineering quality control health prevention and various environmental noise measurements such as factories offices roads homes and other scenes Package List: 1 x Host1 x Screwdriver1 x Manual