CAO GBO LED pen

Wow. Look at all those TLAs.

I noticed a LED pen (like mine) in the GBO. I wondered if it was red. I opened the case, removed the protective cover from the switch, clicked it on... Nothing. Dead batteries?

I opened it up to find 2 tired looked AG13 batteries. I tested them with one of the CAO voltmeters. Barely moved the needle.

Hmm. These things look exactly like my LR44 or 357 or S76E or whatever the hell they're called... From Astronomy Box α, I popped in some of my spares. Presto! The GBO pen is back in service.

It was red.