Product review (2 stars): Cute and handy if you don't care if it's right
Bought the 2-pack, and have had them side-by-side for a few days.  They don't show the same temperature or humidity. I don't expect them to be perfect, but I would hope they could at least be consistent between themselves.  Sometimes it's a degree or two difference, sometimes it's more.  At one point they were showing an 8% difference in humidity, which I consider pretty significant. So they don't match each other, they don't match my thermostat, and the difference between the two doesn't match itself from one hour/day to the next.