This filter is really odd but in a great way. The 3-in-1 nature is really useful. The CPL and ND filters are great enough to warrant the price, but the black diffusion feature is a really cool add-on. The quality is on par with K&F offerings, which is great.

(EDITED 033125) I've now used this filter enough in the field to weigh in a bit further.

One of the remarkable things about this is the ultra smooth nature of the rotation when adjusting the ND. It createa a far better transition in your final product than say the built-in ND filters on a C70. If you have to react to changing outdoor lighting, this is the way to go because ND changes become almost imperceptible to the end viewer. Other adjustable ND filters I've used are not as smooth as the action on this item and cause some visible transitional issues

The black mist diffusion is 1/4 and I would love to have a 1/8 version. The 1/4 does a really good job but for my applications, I would rather have less diffusion than more. If it were 1/8, I'd likely never take this off my camera.

The build quality of this filter is top notch. It feels very, very solid in the hand. The rubberized areas are really pro feeling and make this feel like a filter that cost quite a bit more.

K&F really knocked it out of the park with this filter.