The right angle viewing attachment show above will fit the Nikon F, F2 and F3 (DE-2) as well as the Nikkormat FTn through Nikon EL2 and I'm quite certain back to the Nikkormat FT. As I recall the image size was reduced in magnification. If the camera had a light meter its operation was not affected. It will also fit the Nikon FM and FE family of cameras including the FM2n, FE2 and FM3a. A camera repairman friend opened an FM3a and confirmed that it was NOT and FM series camera but rather an FE2 with a hybrid shutter and a few extra buttons for back light compensation, etc. Anyway the right angle finder is close to universal among better Nikon cameras over a span of years.
The Nikon F may have had a 6x waist level finder but my guess is it was only seen in prototype. The Nikon F2, DW-2 finder fit the Nikon F perfectly if the name plate was removed from either the DW-2 finder or Nikon F body. The Nikon F family of 6x waist level finders are the DW-2, DW-4, DW-21, DW-31 suitable for the F2 through F5. I still own the DW-2 though DW-31.
Anyway the right angle finder show above was near universal for better Nikon cameras. It will not fit the high eyepoint cameras such as the F3HP, F4/F4s and F5. There may have been a threaded adapter ring to allow its use on the high eyepoint Nikon F cameras noted.
I owned one of the right angle accessory attachment but never liked it probably due to the reduced viewfinder image magnification. I probably went out and bought a DW-2, 6x finder for my F2 the same day I learned of its existence. The DW-2 and DW-4 showed significant barrel distortion. The DW-21 and DW-31 were much improved regarding distortion.
Dave
Do I get a prize for Nikon Trivia?