My first Leitz item - identification needed

[std]

Hi Guys,
I've got this accessory viewfinder in a combo with Kiev rangefinder.
Looks wider than the 50 mm should be 35mm.

I see there is a similar viewfinder named Leitz WEISU but this is not exactly the same.
Can you help me identify it.

Thanks

[Kathmandu]

http://www.l-camera-forum.com/leica-wiki.en/index.php/WEISO


Page 14 in this manual has your Weiso.
http://www.cameramanuals.org/leica_pdf/leica_accessory_guide.pdf

The one on the right looks like the one you have.

[std]

Thank you Kathmandu
That's a very helpful document.