Usage Tips:Features: AUTO Alarm Icons: the noise alarm face icon will automatically switch when the decibel at different level. [Green Icon]Less than 60dB;[Yellow Icon]60~75dB;[Orange Icon]75~85dB;[Red Icon]More than 85dB High Accuracy:Decibel Level Measuring Range: 30~130dB , Accuracy: ±1.5dB; Frequency response range: 50Hz ~8.5KHz; Temperature Range: 14~140°F; Humidity Range: 20~85% EXTRA LARGE LCD DISPLAY & WALL MOUNT: Our digital sound level meter is equipped with a high-definition backlit LCD screen, so that you can effortlessly read it throughout the day at your convenience. Unlike handheld sound level meters, our premium wall-mountable dB meter is simple to set up and perfect for continuous monitoring. VERSATILE & LONG-LASTING: Our classroom noise meter can be used all over your space. It's wall mountable with a 10ft power cord, flat-bottomed for placing on tables, and lasts for hours unplugged with a 2000MaH battery. Also, it can be a home theater SPL meter by the TV or in your garage workshop. BONUS FEATURES: We've included bonus HUMIDITY and TEMPERATURE readings in addition to bringing you the best decibel meter we could. And to top it off, the sound level tester has 3 ADJUSTABLE SPEEDS (1. Fast 2. Medium 3. Slow) to make reading it a breeze. Color: As Shown Material: ABS Package Contents: 1X Decibel Meter 1X Mounting accessories 1X USB charging cable 1X English 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.