18650 LI-ION battery holder. 

Holds 5 LI-ION 18650 cells. They can be held in with a rubber band. When held like this

they are very easy to remove and easily accesible for flying Nano long range drones.

Can be stacked using 5.2 mm magnets wich can be glued in the corners on the top and bottom.

I can easily change the diameter of the magnet if you let me know :)