Be aware that this unit requires it to be near a USB outlet and plugged in most of the time in order to work. There is a lithium button battery inside the unit, however it is only meant to keep the date and time current when it is unplugged for short periods. There is no easy access to this battery when it needs to be replaced. The entire back of the unit must come off to do this. I can't easily tell what kind of head the screws have because they are deeply recessed. If you wish to hang this unit on a wall without USB access you will need to have an electric outlet adaptor. It does have a 4-5 foot USB C cable to make this easier. It has a kickstand for table top use. It is big and imposing on a desk, so it will need to be moved somewhere else.I struggled a lot trying to figure out how to get this item to work. I will start at the bottom line of info and move towards the top. The date does not fully work because there are light bars in the year that do not light up. In 2024, it is the 20 which is annoying to look at. Over a period of days these lights have never come on, and I doubt they ever will. I figured a way around this would be to place black tape over those two digits to make the date look more normal. The clock works in one mode only which is 24 hours. I would think most people might like the option to have a 12 hour clock with AM and PM for home use. The date and time have stayed accurate over days once set.To the right of the time are the temperature and humidity readouts. Fortunately, at least the temp can be changed from Celsius to Fahrenheit. Both of these readings seemed to vary too much from my higher quality indoor/outdoor monitor close by. The temp was off by 5 degrees, which is just too much of a discrepancy to be useful. Not sure why, but after three days both of these seem to be a much closer match to my other monitor.The decibel digits are also annoying to look at because it also registers in tenths of a digit. Since sound is constantly fluctuating, the tenth of a digit is constantly changing every second or so. No way is this thing going to sit on my desk and do this while I try to work. My fix would be to put black tape over the flashing digit since the whole numbers are enough information. There are a range of different colored bars to the right of the decibel digits, which have mostly stayed green on my desk. Not sure why, but to the right of the colored bars, there are a series of redundant smiley faces in colors as well. For the first few days the smiley face was constantly red while the bars were green. The red face did not appear to ever change or be working. Last night the smiley face turned green for the first time. These symbols are actually fairly faint and hard to see, which is just fine with me. I think most adults might prefer the bar reading better, which is much more visible and prominent.To be perfectly honest, this product was frustrating and took up a fair amount of time to assess. Giving it three stars was generous. I hope by writing about my experience it will help you to decide if you want to deal with its quirks, or not. I am unsure how and where I might best use this monitor, but I am glad I waited a few days before I wrote this review because the unit did improve in some respects and is more functional. Lastly, I cannot comment on the reliability of the decibel meter because I have never had one before. I think where I am headed is to find a high quality, portable, decibel meter, which is handheld and will consistently work when carried around to different locations.

First off, you are likely getting this meter because it measures sound. In that regard I'll mention the following: sound level reads lower than actual by anywhere from 3-10dB. I can't figure out if it's the weighting function or why exactly it is inconsistent with my other SPL meters. Minimum SPL is 44.0 dBA. There's no reason this needs to display SPL in 10th of dB, and as another reviewer noted, it's quite distracting to see the numbers constantly changing. The microphone port is a small hole near the top right of the display facing out. Time is 24hrs only (though I'm becoming more accustomed to that format). There's a fair amount of bleed through from unlit digits. This gives the unit a more cheaper appearance. Temperature doesn't appear to be terribly accurate either (currently reading 81F in a room that is 77F). It appears to keep reasonable time (haven't need to set the clock since plugging the USB in). The manual warns that the internal battery (button cell) is for saving time settings only, but upon removing power the whole device stays powered on, so it gives the impression that it's meant to be battery powered. You can power it from a USB power bank or wall adapter. My power meter reads ~2W (5V, 0.5A) so any old power adapter you have lying around will work. The white power indicator light on the side by USB port is brighter than it needs to be.