Utilitarian, but not a snug fit for 18650s.
This works fairly well to protect the batteries from dents and puncture damage and from coming into contact with metal things that might discharge them (like a pocket full of coins — *that hurts*.) But the 18650s just sort-of rest in the box and rattle quite a bit, rather than being held firmly in place.
The clasp works pretty well, but the whole case doesn't snap / seal when closed — meaning the box isn't water resistant at all. So if you're out, say, camping / hiking / fishing, put the box in a ziplock bag and you'll be good-to-go against the elements.
Reviewed by: Mason from Texas.