What's important about a battery case, anyway?
Well, it needs to hold the cells securely so whether there's just one or it's full, there's no rattling about...
And it needs to close securely, so it doesn't open while in your pack or case or luggage...
And it needs to open reasonably easily despite closing securely...
And it needs to be cheap, to boot.
The Tenergy 4 AAA case actually does all these, although the "opening reasonably easily" can be a bit of a challenge if you have weak or arthritic hands.
I'd be careful when opening the case if it has been left out in the cold; let it warm up a bit before trying to force the tab down to pop free the mating clasp.
The Tenergy 4 AAA case is a "scaled down" version of their 4 AA case. Some might use the AA case for both AA's and AAA's if extras for both are needed.

A much safer way to carry batteries than rolling around loose or in a cardboard box.

Useful for the storage of loose batteries. I have had these plastic cases for a few years now and not one of them has failed yet.

I like to keep all my batteries in plastic cases for safety reasons. These cases work great and are clear so you can see what type they are.

Great for organization and traveling.