Product review (2 stars): Inside/outside units didn't seem to communicate.
I bought this some time ago, and the outdoor unit did not seem to work.  I didn't feel that it was fair to complain to the seller, since my patio faced west and it was close to impossible to situate the sensors as suggested.
I moved into a new home this April and the outdoor unit still doesn't work -- and I did change the batteries.
The inside display appears to be accurate -- but not worth much to me, since I can look at my thermostat!