Like SMBooth said, color will be no problem in these roll film backs - my Dayi doesn't even have red plastic in the window (it's just a hole), but the paper backing on 120 film is well-designed to stop that light from affecting the film. I love using this back for the cheap access to color that it gives me on my Linhof.

I will try to write up a more comprehensive review of my DaYi 6x12 back sometime, but the short version is that you should possibly expect to deal with some fixable QC issues that result in light leakage (at least that was the case with the 6x12 DaYi I bought recently). Mine in particular suffered from incredibly bad light leaks through, around, and near the port for the dark slide. Destroyed several rolls of film.

I spent some time spent taking it apart along with judicious tweaking of certain bits and application of electrician's tape and solved the problem completely. It is solid otherwise, and I expect no further issues. Now that it is working, I love it. But, I have to say that light-fastness seems like such a fundamental property for a piece of film-handling equipment that I find it sort of inexplicable how a brand-new film back could fail so miserably on this basic charge. I guess you get what you pay for - it costs about 1/10 what a Linhof back would cost. At least it was easy to fix.