What is this called?

[Mikey7777]

Hello All I just joined this great site,Iam new to collecting vintage camera's. I got a box of vintage box camera's this piece was in it.
I have done research on this part I think it's a flash box the piece has no name on it.
If Iam wrong does anyone know what this piece is called?
Thank you

 

[compur]

You need to post photos that show the whole thing but from what you have posted it appears to be a viewing hood for a rollfilm camera.

 

[480sparky]

A hood with a magnifying glass for focusing.

 

[dxqcanada]

That embossing ... M ... hmm, Mamiya ?

 

[Nikon photographer]

It's a waist level finder focusing hood for a Mamiya C3 TLR

 

[Douglas Brown]

Looks like a waist level finder. Back in the day, I used one on a Rolieflex TLR. Open the waist finder hood to see the focusing screen, flip a magnifier up for more detailed focusing, and I could even flip an exterior plate down to reveal "sport mode" and shoot that parallel instead of looking down. Pretty cool for the TLR camera of the time.