From what I've seen on the forum, the 2.1 will use the same 18490 batteries, the 2.1 will be rounded a bit more in the back and will have a larger drip well to accommodate more of the rebuildable attomizers. I believe that is the only difference from the 2.0. Congrats on your new REO!
Sorry for the stupid question, i am going to put a order in at my local vender for batteries. What sized battery will the 2.1 run? Same as the 2.0?
Cheers
Aaron