It claims to be a sealed lead-acid 6v battery.

My understanding is that these will eventually dry out and need to be refilled with distilled water.

Any hints on how to get this little cell refilled? Doesn't seem to be capable of absorbing any water, the opening is too small.

I'm debating drilling a very small outlet hole next to the fill hole, to allow the air to escape, and then filling that hole with epoxy afterwards.