Q
does this have filter threads on the front if you wanted to add aditional filters?
Answer Question
A
No it does not. You have to place other filters inside/before this filter as I did on a recent trip to Yosemite. The fader worked great, however, in enabling me to shoot movement in flowing streams and waterfalls. I appreciated the filter's adjustability and I no longer have to carry a set of.3, .6, and .9 ND's around with me