-The Operation of 1 to 4 18650 batteries (in series)
-The Battery landing indicator (3Small LEDs on the side)
-One-Off switch
-Ladefunktion In the box (which I do not but use)
A single cell (3.7V 2600mAh) enough already for the charge of my smartphone. If necessary I can the cells between the torch and box change, unless you screwed the box again.
So for hobbyists and owner of this battery type is a super thing to distribute its existing resources makes sense! Rather not recommended for people who do not have this type of battery, since the fitting with all 4 cells probably beats with extra 40 to book ... secured cells provided !!!