85mm Neutral Density Soft Edge Master Kit (6-Filter ND standard and graduated kit)

The Formatt-Hitech filter system works very well -- the filters are of high quality, the frame comes off easily so that you can store it in your camera bag, with the filter attached, and put it onto and take it off of the lens when needed. Exactly what I was looking for, but with one problem -- the lens cap does not fit onto the front element of the lens when the adapter is on, so that if you take the filter frame off and on, then you're not protecting the lens. I solved this problem by buying an item called a "lens hoodie" from bhphotovideo.com (it takes the small size), and this works very well.

I find that the Hitech filters do a very good job of preserving the true colors in the scene without any color casts. The only reason I would not go 5-star is that any plastic will scratch more readily than glass. I know this and take pains to handle my filters carefully, cleaning only with microfiber cloths. Definitely recommend this brand.

ND and soft graduated ND plastic filters by Hitech; works great.