And you know where they insert them dont you  ?.....

Yes, under the armpit..............

Why the symmetrical bulbous ends though ? 

pnc, can you load a pic using the loader here as your pic comes up very small.

Select the icon 2 to the right of the smiley, scenery looking icon and follow the prompts. If you have the pic on your desktop, very easy.

quick search found these

https://www.ebay.com.au/itm/Vintage-PHOTOGRAPHIC-THERMOMETER-BRANNAN-LONDON-in-Steel-Case/1832167253...

https://www.ebay.com.au/itm/Vintage-1950s-Glass-Medical-Fahrenheit-Thermometer-Metal-Sleeve/31215104...

It is definitely not a medical thermometer case David.....I have had a number of those over the years and they are a lot smaller that then item in the OP.

If both ends screw off I doubt that it is a thermometer case of any kind....there would be no protection if both ends came off.

Will try my best!  

Yay!!!  Success!!

A baton of some sort?

https://www.google.com/search?q=baton+images&client=firefox-b&tbm=isch&tbo=u&source=univ&sa=X&ved=0a...

a real head scratcher of a mystery.

the fact its got plastic in it sort of makes it reasonably modern.

when i worked in the defense industry workshops i saw lots of strange impliments with metal cases but nothing exactly like that.

anything fragile was kept in metal cases.

but then it could be an impliment in itself.

could easily be medical too.

i'm going to call it a 'dooflangy'

boss tells worker 'go get me a dooflangy! and be quick about it!'

then theres the medical version

doctor "forceps, swab, suction quickly! OMG, give me a DOOFLANGY!'

any other ideas?

Haha you'd wanna make sure that you get the correct dooflangy for the doc otherwise it could be the difference between life or death for the dooflangy patient.

Aha it's a curtain ring holder hahaha