Not very beautiful or glamorous, but a load optimally 9v batteries "without killing them!"

(+) Charger "intelligent" (*) but that is not seen in the design ;-)
(+) Two independent charging circuits: each battery is handled on its own merits
(+) Automatically Made the difference between NiCd and NiMH batteries (with / without memory effect)
(+) Not too expensive for a "smart" charger (about double of a "basic" charger)

>> Highly recommended if you want to load quality batteries (and use a long time)

() Not very nice: cheaper products are more elegant!
() No indication of the time left to wait for the end of charge (a small level meter would be more useful than a simple LED)

(*) Adapts the charge to the battery and prolongs its life = best compromise between speed and load protection of the life of the battery. I have several years of positive experience of "smart" charger, and confirms the clear difference with shippers "passive" (or economic)