replacement of eyepiece sought for Hassleblad NC-2 prism finder

hello,I recently bought an NC-2 prism finder for my Hassleblad 500CM. The rubber ring (not the eye cup) around the eyepiece is partially coming out of its slot and is starting to fray. Does anyone know of a source to replace this ring? I already contacted Hassleblad/Bron and they said no. thanks

According to an old Hasselblad catalog I have, there are interchangeable eyepieces for the prism viewfinders including the NC-2. They range from +3 to -4 with one being 0 neutral. That may be what you are looking for. Many years ago I changed the one on my PM-5 so I could focus without my eyeglasses. You may need to get the entire eyepiece which is easy to replace and just screws in.

http://www.jeffreyglasser.com/

what I am looking for is just the rubber that surrounds the viewing opening.