I use 4.8v batts but I dont believe they are 18650 exactly, Jason over at electonicstix carries them and I believe Bruce over at COV may also. You do need a special charger for them as well if they are the same ones I'm using, it is a modified 18650 single charger, do not use a regular charger for these Batts !! You also do need some of the small rare earth magnets to make them work in some
mods, unless you are talking about something new that I am not aware of these Batts are made up of Ni MH Chemistry and are 4 x 1.3v Batts and are 600mAh