I have one of these. Bought it at Wal-Mart a few years ago for about the same price. Its a standard battery charger and rechargable batteries. They work well for digital cameras and things you need rechargable batteries for.
I believe the saying in batteries is that you either 1) charge quickly and sacrifice battery longevity or 2) charge slowly and maximize how long your battery will last (i.e. how many cycles it will last). As for me, I’m sticking with Eneloops.
I have this charger. It does charge quickly, and at first the batteries work very well, but the batteries that came with it no longer hold a charge and I’ve only had it about 6 months.
I also frequently forget to switch the little 2/4 switch on the top when I put in a different number of batteries, of course that’s my fault not the unit’s.