The top plate to a black Nikon FM3a. Not quite on-topic but.... Anyway, some mysterious person -- for once, not me -- must have dropped the camera and not told me about about since I realized the other day that the pentaprism was dinged and pushed in which, in turn, interferes with free rotation of the Ai tab around the lens mouth. So I bought a replacement to insall that is now on its way. I hope it fixes the problem.