All this back & forth has me confused!

I feel like I have a learning disability & can certainly sympathize with those who do--when I do purchase spare batteries/charger...what exactly should I look for using the Nano. CR123 protected, correct? If you guys are having hassels with some places, I don't wanna deal with that. I got enough frustrations going on. (And no offense to anyone, but it would be silly & not very cost effective for me to send off to another continent for simple batteries)