TES 5321 PM2.5 Air Quality Monitor

We got this product and it worked great. We packed it away for 10 months when we have fire season and need to check AQI. Wonderful for a week and then the batteries stopped working. Changed them out multiple times with multiple brands and no go so it only would work if plugged in. Then, 2 weeks later the entire thing stopped working and will only read an AQI 250 regardless of where it is even if we know that the AQI is different. I have contacted the company. We will see what they will do about it. I hope they honor their product

Worked great for about 2 months of occasional use in a home wood shop. Then it began reading consistently 60-80 high. For my purposes, its not worth paying a lab to calibrate it every few months to make it work. Paid $45 dollars shipping to return it to the factory (in Asia) for repair. Repair was free. Process took 6 weeks. Have had the device for 2 months since repair and it works good.

Worked great then stopped reading air quality after a few months. Reached out to manufacturer and zero response after multiple emails.