is boa.
If you are sure that it is a 33mm push on mount that you need, I have one with a retainer ring (Series VI) that I'm not using. PM me if you're interested.
I was saving it in case I bought a 203 Kodak lens, but I wound up with a Wollensak 203/7.5 instead which takes a 39.5 push on instead.
I wouldn't worry too much about the push on filter holders being loose or wobbly. If you play with the tabs a bit you can get them to sit on your lens barrel
very tightly.
Derek