Gene51 wrote:
Cokin, IDX, Lee, Nisi, Formatt-Hitech, Benro, Kase Wolverine Series K9, PolarPro, Wine Country Camera filterholders/Blackstone filters. Haida, Marumi, etc etc etc. There are quite a few.
I did lots of research on all of these and read all of the pros/cons before deciding. Took me a good year, but I got there and I'm happy.