You're not alone, I have the same issue with an aquatica III for my nikon F3, bought it today Threaded domes have been in production until the F90 housing, than oceaneye switched to user friendly bayonet(1990-1995) You can find a vintage plexiglass dome for $$ Ask someone to make it for you, $$$ Ask oceaneye, $$$$ Star machining aluminum or plastic and find you way, $$$ Good luck and keep film alive