Dual Battery Mods.

Dual battery mods are the most popular type of mods, they can go up to around 200W and the batteries last longer than the ones with one battery, and a lot better than the build in ones because in time battery performance drops after some time, but with dual battery mods you can just swap the batteries and there is no need to replace the whole unit as its the case with the built-in battery ones, so it is going to save you some money in the long run,

Mods with 2 replaceable batteries.