Product review (5 stars): Bought two in one week! Great Buy!
Bought one and got it.
Within two days, I turned around and bought another for another location in the house. BEST PART, all I had to do was put batteries in the indoor unit, instantly synced with the existing outdoor sensor! (Hence, a spare outdoor unit, if ever needed)
This is about as accurate as I can tell by local websites outdoor readings and is dead on to my interior home thermostat!
EXCELLENT BUY!

Follow directions well for the outdoor sensor! I have mine under a 16x16 lean-to. It gets no sun, element exposure and plenty of moving air.