Interesting, I've never seen fire suppression in pods before, it's always been in upright cylinders.
Just a guess here, but I would think that three spheres would be able to vent their fire suppressant faster than a single cylinder. That might improve their effectiveness.
Says "Fire suppression" and "non-flamable gas" on the labels. I think that pretty much explains it.
I'm guessing the electrical connection is a pressure sensor. It probably throws a warning if the pressure gets low.

Thx for the info, and stuff, guys. I was just curious. I have never seen anything like that before, and didn't have time to read the labels.
They use squibs to fire them. There's a burst disk on the outlet of the tank that's ruptured when activated. They used to be somewhat common back in the day here in my AO. I've not seen that type of tank used with FM-200. The ones I've seen were Halon 1301.
We still install FM-200 by the way. It's one of a few chemicals that replaced it for new installations. We can still get it (Halon 1301) to recharge a system after a dump (discharge). However, None is being produced for civilian use.
Those spheres make GREAT BBQ pits BTW.