I’m pretty sure that’s right — 1, 2, 3, or 4 cells
and less sure it can take both AA and AAA at the same time?
I’m also curious with all these AA/AAA chargers what you think of using them for C, D, or 4/3A NiMH cells (connecting with alligator clips/magnets)
I know it would be slow at best.
I also saw somewhere* an adapter that would slip into an AA slot to hold a C or D cells
_
Edit: everywhere: charger adapter AA to hold C or D cell - Google Search