It comes with a sleeve that allows me to use an 18650 instead. I'll be doing that at first as I have no 26650 batteries. I grabbed it because it was on sale, and it perfectly fits a very large rba that I also bought. I'll be putting two coils on the deck and aiming for about 0.75 Ohms. I'm looking around at 26650's but the info I am finding seems to be kind of old. A lot of stuff from 2016, I suppose because the 20's and 21's have been all the rage this year. Is the iJoy still about the best looking 26650 out there or are there others that I should consider?