AW 18650 IMR 2000mah in my Provari. When the time comes I will check what's compatible in higher mah varieties, but it will probably always be something with Japanese made cells inside.
I get an all day vape from my batteries. Sometimes that means I change it after supper, but usually that's because I stopped using the first one at 3.5v and charged it before the battery began to get stressed to cutoff.