Eye cup shows some wear, mostly around the upper rim, but it looks good. I don't see anything damaged. I don't know what camera brand it might fit. Maybe it is for scope? Or maybe for microscope eye piece?

ID is 29mm, it should fit finder with 28mm OD. Please note that you get rubber part only. It does not have any threads. 

Eye cup will be mailed just as pictured, so please look at the pictures above.  I will pack it well to protect it from damage during transportation.

Shipping is free within USA and $7 via first class USPS air mail service worldwide . You can choose faster (and more expensive ) shipping if desired during checkout.