Backlit LCD Screen: This sound level meter measures noise levels in decibels and displays them on a 1.25-inch LCD screen, making it easy to read through a large screen design. Long the backlight button to turn on the backlight, making it easy to view even in dim light Max/Min: A sound pressure level (SPL) meter has a maximum or minimum measurement value, which represents the maximum/minimum (high/low ) value of the sound produced over a certain period of time. The data retention function can freeze the current reading based on individual needs for sound measurement Fast/Slow Measurement: The sound level meter has the function of converting fast and slow response rates. The rapid response rate is measured in general environments using a time constant of 0.125 seconds per time. The slow response rate uses a 1s/time constant, which is used for measuring environments with relatively large changes in noise levels Easy to use and fully functional: anti slip design, portable noise meter is easy to carry.When the battery level is low, a low battery indicator light appear on the screen to remind users to replace the battery in a timely manner(No battery) Power Supply: Powered by 2 * AAA batteries (Not included batteries) Color: As Shown Material: ABS Package Contents: 1 * Noise meter 1 * Screwdriver 1 * Chinese and English instruction manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.