The Smart WIFI Temperature Humidity Sensor ST1 is working perfectly for why I purchased it. I actually purchased 4 of them to keep in my refrigerator/freezer and 2 stand-alone freezers. I needed to use Energizer Ultimate Lithium AAA batteries. Regular Duracell alkaline batteries were not working in the subzero temperatures. I expect these to last for decades. Time will tell.
Thanks,
Paul S. Heimers

Very good value

Excellent

Temperature reading is about 7 degrees off, but works for a low temp alarm.

I currently have six of these monitoring in various places. All of them are performing accurately and well within the specifications listed. Four of them have been in-service for around two months, and I purchased two additional units to replace units from a different company. I will update a few months from now!