I have two styles of rubber eye-cups that fit my “K” series film bodies. The smaller one on the right (43mm wide) is the “K” series accessory “Eyecup II”, so no questions on that one.
The bigger eye-cup on the left (47mm wide) also fits the “K” series film bodies perfectly and does not have an “M” marked on it to identify it as an “M” series accessory. (The “M” version would also have a larger viewfinder opening.)
Both eye-cups have “Asahi Pentax” marked on the top and “Japan” on the bottom.
I’m thinking it’s a screw-mount eye-cup, can anyone verify this? It would be a little surprising that Pentax changed the eye-cup size when they released the “K” series version, as most of the screw-mount viewfinder accessories were just repackaged as “K” series accessories. (Refconverter, magnifier)
Thanks, Phil.