Product review (4 stars): STATISTICALLY SIGNIFICANT VARIANCE BUT MANAGEABLE
In this 4-pack, I found statistically significant variation in results among the foursome.  Temperature readings are very close with the variance coming in the RH (relative humidity) readings.
The group was tested in varying room locations over a 24 hour period, and nearly side by side.  Readings were inconsistent among the group, and varant from another unit in use (EXTECH 445703)

But, on a positive note, once the variances are understood, and compared to other devices, such as the EXTECH 445703, as well as the national weather service, the units are useful.
I don't need an exact reading on humidity, or temp for the matter, so I'm not disappointed.

Decent product for the price.

CARPE DIEM