Low Temperature Freeze Protection - Heat automatically turns on when temperature goes below 40° F (4°C). Protects pipes from freezing. Larger Back Lit Display - Makes viewing and setting the temperature easy and accurate.
My old Robert Shaw digital thermostat was like this one (same model number) but it was operated by 2 AA batteries. It still works fine and is 15 years old, but the cover broke and the batteries kept falling out.
This replacement apparently needs to be wired to the heating/cooling system directly somehow, there is no battery compartment or door, so I may have gotten the wrong model.
Not a big deal, - I took the board out of the old one and put it in this new cover because the cover is what actually needed replaced. I kept the new board for future use if I get an electrician to look at it.