We actually had a couple of these at my camera club until a few years ago. I scavenged parts from the two to make a couple of special purpose flash heads.
They are just general purpose 1000 Watt lights mostly used for photography, cine, or theatrical purposes. They could be used for video, but most likely they were purchases long before video became commonly available. Bulbs should still be available from places like "bulbs direct" but are likely pretty expensive.
The two rods in the middle are for a domed diffuser/reflector to subdue the direct light from the bulb (so the output is more even over the entire reflector). Looks like you did not get that part.
The center slider allows you to focus the light somewhat.
I would give it a test drive, you may like it. But I would carefully inspect that braided fabric cord. They have a tendancy to break down with time. But a good visual inspection will tell you if is still vital or not.
Enjoy! Lon