Thanks Aggie for the offer. I may take you up on that. I, for some reason I don't know, have an older Cokin 77mm threaded holder that 3.25" wide (maybe that's what 3" actually are?) that rotates 360. But I don't have any filters that fits Don't ask cause I don't know hehe

So are these 3x3" filters large enough for a variety of lenses? Maybe I can find the stats of lense width online. As it seems you just need to be sure the filters wider than the front element?

Good find Robert, I'll keep an eye on something like that if I need the larger 4x4 holder. But I'm thinking like Lee, and maybe just holding in front of the lens for ease of use. The screw ins are spendy for a decent one. The gels seem more affodable and pack up flatter as well. Just something to think about.