To save everyone the trouble of trying to find the pic, here's a reminder -  

That would be wonderful!! Thank you so much!!! 

Done and done: https://www.reddit.com/r/whatisthisthing/comments/8pzhbp/hoping_to_identify_this_hollow_metal_rod_ap...

Users may ask more questions, which I'll relate here if I need to clarify something.

One suggestion so far, of a wedding certificate holder (this would make the plastic rings a later, unrelated addition).

Pics of certificate holders, most seem a bit more fancy or engraved, though. 

At 18 cm, it would be too short for a marriage certificate or birth certificate - that is, for a modern certificate. (They're A4-sized nowadays.)

A certificate issued before the current certificates became standard could be a possibility. Perhaps even something like a school certificate...?

But I agree that nowadays certificate holders are more ornate.

The bulbs at either end must be a clue to this item. They may not relate to what's inside (aka my joking suggestion of a holder for a cotton bud - giant-sized), but rather to how this container thing was stored. The bulbs would suggest that it was placed horizontally over two sides of something, or over two bars or hinges on a wall...

The fact that the bulbs screw into the rod is what's bothering (or intriguing) me, as that's relatively unusual for something that's just a curtain rod (sample or otherwise) or some kind of holder. It's hard to tell from the picture, but it also looks like it's chrome-plated rather than stainless steel to my eyes, so may have been a bathroom fixture of some sort (towel racks etc are usually chrome plated). 

A further suggestion has been made that it's from a more upscale toilet roll holder, and the rings may be used if the roll is bigger, or pushed aside if the roll is narrower. It sounds feasible to me, but still couldn't say for sure.

Just to clarify, is 18cm the end to end length? And / or what is the length of the rod section? 

When - and if - we find out what it is, it will be either

Or