Funny, I found one that looks exactly like the one in your photo on Amazon, they sell as a 3 pack or 1 pack.
It does not fit while in the case, but does fit when out of the case (though very tight) I have mine up there now, and the other two in other cars, or you can keep all 3 in it.
I know in audi's in Germany they have cut outs in the plastic to show the reflector when stored up in the trunk so that when the trunk is open you can see the reflector at night, for added safety.
Here is a link to the item on amazon (if it does not work, search for "Fasmov Triple Warning Triangle Emergency Warning Triangle Reflector,3-Pack" ) - it is $15 for 3.
https://smile.amazon.com/Fasmov-Warning-Triangle-Emergency-Reflector/dp/B016MBHC56
They also sell a single, but the cost of that one is $10 for one, so go for 3 for $5 more.
https://smile.amazon.com/Fasmov-Warning-Triangle-Emergency-Reflector/dp/B01AOS717M
Quality is ok, the rubber feet have a hard time staying on though.
For $15 for 3, I would recommend them.
Seems just as sturdy as a Volvo one, but the feet are slightly shorter, so I am not sure how they will hold up in strong wind from an 18 wheeler blowing by like the ones with the sand base do.
Remember, this euro style is not DOT approved, only the ones with the sand in the base are as they euro ones don't pass the DOT wind tests.
That is why none of the euro cars (or Genny) have them from the factory.
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Ill try posting photos of the amazon / Fasmov triangle in the Genny (2nd gen):
Here it is set up (but legs not fully extended (from amazon), it has plastic fabric/ribbon for the fluorescent orange like the German car brands use (that is what you see on the top right of my photo, as it is folded behind the reflector) :
