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.