Antique/Vintage Heater?

Bought this today, without knowing for sure what it is
Google Lens thinks it's an exhaust
Is it a heater?
approx. 16cm in total, container 10 cm, with a diameter of 7 cm

 

??

 

container of a sort?

 

Snow or sand or soil sampler?

 

Perhaps two lids for a map storage case (or two storage cases), similar to this -
https://sutleroffortscott.com/product/largetin-field-map-case-c427/

 

As one fits perfectly into the other, it seems that they belong together

 

Apparently I'm not the only one trying to solve this mystery.
Here https://www.menterwolde.info/regio/...werp-dit-is-en-waar-het-voor-gebruikt-wordt'/ someone posted an identical item, asking if anyone knows what it is. The question was posted in 2017, so hopefully he found the answer by now. I've sent him a message, to see if he can shed a light on this.

 

Based on the similar container for storing maps, I would imagine it is designed for storing/protecting something. What is approximately 10cm wide and kept rolled?

 

But those usually only have a handle on one side, right?

And with a diameter of under 6.5 cm