Product review (3 stars): Works well for temperatures, less so for humidity
The temperature readings are accurate, but it takes a fairly long time to display the right reading if the temperature changes suddenly (e.g. if you put it in the refrigerator).  When you place the two probes side-by-side, both show the same temperature.  The same cannot be said for the humidity: placed side-by-side, the humidity readings differ by at least five percentage points.  Since this doesn't matter very much in most situations I still consider the device usable.