Inverter

[Kyz]

I have 2 100ah house batteries (not lithium). I have a small Danby 4.7 cu ft refrigerator. I want to put in an inverter for the refrigerator when traveling/when the power is out and possibly run another thing here and there if needed if the power is out. But the inverter will sit by the refrigerator. What size inverter would I need? Pure sine wave? Preferred brand or does it matter? Do I need something else? Battery manager or something? There is no solar. Even though my plan is to sell the RV, I want to buy the right thing as if I'd keep the RV for a long time so not "the bare minimum" to do the job.

There's no info on the paperwork for my fridge on how many watts and it's raining so I can't check the back of it right now. I can tell you that they've almost doubled in price since I bought one. Good grief!