I just bought a "eLeaf iStick Pico Kit "and "2 X Efest 18650-3100 mAh- 20A +include Battery case.
I wonder if this kind of battery can be worked in my machine?
Any 18650 would work with the pico kit
mAh- represents the battery’s capacity. This higher the number, the longer the battery will last on one charge.
and always make sure your extra battery is in a case !!!