This little charger may not look like much, but it's charged every one of my EN-EL4(a) batteries I've had in my Nikon's kit bag. Does 3 at a time, and they charge independently. So when one battery is complete, you can remove it and add another without interupting the charge of the other batteries.

I hooked it up to my one USB charging hubs that gives a reasonable output of the amperage draw, and it looks like it will take a pretty solid USB-C charger at full power if you let it.

Does not get warm, or at least no warmer than room temperature, even when full-charge is going on with three batteries.

Came with three batteries, worked flawlessly with my Nikon D3200 camera. I haven't had them long enough to tell you how long these batteries last, but in an afternoon out with my kids, the dual-battery handgrip did not seem to show any problems or significant battery drain.

So, for a camera that's a few years old, this is an incredibly good piece of kit to add to my gear bag. Since it accepts USB-C I can plug it in nearly anywhere I am, since most of my gear now accepts USB-C.

Zero complaints!