What is this? And what is a Rollei Mutar Filter worth?

[ChrisP]

I don't know where to put this since I don't know what the silly thing is so I apologize if this is in the wrong section. Anyways I recently bought a bunch of Rollei stuff and this came with it. It's obviously not made by Rollei and I have no clue what it is. Any help is greatly appreciated (images below).

Also included in the big box of stuff is a Rollei Mutar 6x6 Yellow filter (essentially a Rollei 67mm yellow filter). Anyone have any idea what it's worth? Again any info is greatly appreciated (I tried ebay and nothing came up and there wasn't really any discussion about them on any of the forums so apparently they're quite rare)

 

[squareshooter]

I think I owned just about every Rollei gizmo made including the Rolleimeter and the Rolleikin 35mm attachment, Rollei closeup lenses and the Rollei bayonet-mount Rollei flash bulb gizmo that bayoneted onto the viewing lens and made horrible photos. But your gizmo is a Zeiss-Ikon and seems to be an attachable focus screen. Good luck.

 

[ChrisP]

So after some research it appears to be a focus screen from a Zeiss Ikon Contarex Special. Don't know how that made it's way into there.

That just leaves the second question to be answered. What is my big Rollei Filter worth?