Which thermostat should I buy to replace

[anaten]

I have 2 nest thermostats, one has been going off and on and now will not charge at all.  I just want to buy a new one, but not have to rewire anything.  Right now I am pulling the controls off  of the working one to use both units...this is what my nest says:

09xxxxxxxxxx display 3.7...

How do I know which one to buy?

[Patrick_Caezza]

@anaten 

Unless you replace your existing thermostat with the same model as you currently have, you will need to move the wires from the old one to the new one.

If you are having a power issue, post a picture of how the base plate is currently wired.