I forget what you call it, but Zojirushi also produced a slow-cooker-type pot that requires no electricity. You boil water in the outer pot, insert inner pot containing meat and veggies, seal it and in eight hours you have perfectly cooked stew. It was very useful during our cross-country RV trips. At home, it uses minimal electricity and you don't have to be concerned about electrical misadventures if you're away from home.
If you can figure out what you used, I’d apreciate it. I assume it is a thermos of some form. I like to read up on these things.