The supplied rechargeable batteries (NiMH) are Duralock type, guaranteed 5 years and quite good capacity (1300 mAh each AA, AAA 750 mAh each), but there are better still.
Only these two formats are supported (in NiMH only, of course), otherwise lean for example on the charger that is very versatile (he even accepts 9V batteries.)
Recharging is fast enough (there are a few more years, we had 10 to 15 hours of recharge!), Yet Duracell chargers is still faster, but be careful anyway because too fast refills are deemed degrading batteries faster. Better have a pair of old rechargeable lead batteries.
The extremely simple device to use, although we may regret it is not possible to charge one battery at a time other shippers (more expensive) do and it's convenient for some devices using a number Battery odd. Red signal lights flash in case of error or charging problem, they turn green when charging is complete. Only drawback to this wall charger, it is quite broad and could prevent the use of too close socket (eg a power strip.)
Adopted.