What kind of special plastic board is this?

[ksthlm]

I have tried searching all possible combinations on Google but nothing similar comes up.

Since the text was cut off in the picture like this:

"Looks like thin alu.alloy on both sides"

It's the "lid" of a custom-built terrarium I have come across.

 

[Snappahaneklanen]

I tried searching for sandwichskiva, found this: https://www.rias.se/plast-till-indu...ation/sortiment-data/alu/skivor-sandwich.aspx

Could it be something like that?

 

[ksthlm]

I tried searching for sandwichskiva and found this: [link]

Could it be something like that?

That's awesome, thanks!