Stereo attachment for the 9x12 Contessa Nettel / Zeiss Ikon Deckrullo; undocumented?

[Ron (Netherlands)]

Just got in the mail this - almost looking mint - stereo attachment which fits my 9x12 Deckrullo.
I bought it since I had seen some before but never with these measures (and till now hadn't got a stereo Deckrullo).

For the ones not known with this camera:
the most non-rare stereo Deckrullo is the one for 6x13 cm plates both in black or tropical teak (https://collectiblend.com/Cameras/Contessa-Nettel/Deckrullo-Nettel-Stereo.html) ;
Further I have seen quite rare attachments for the one with 10x15 cm plates, only in tropical teak;
and have seen one with the attachment on for 13x18 plates also only in tropical teak (currently on ebay).

My camera is the more older 9x12 in teak (will post a pic soon); so it is not the 6x13 model and my attachment would not fit that model.

Are you aware of other types/combination?
.....and if possible show yours.

thanks all