Anybody remember Petri? They used the Nikon specs to try to compete. You could interchange their filters and lenses for a lot less money than the Nikon brand commanded back in the 1970s. My eldest daughter showed the most interest in photography, so gave her all my gear.
I remember that brand. I was in Japan in 58-59 & a Petri was quite a popular brand at the base exchange. Stuff there was quite inexpensive at the time...if you had any money to spend.