This is a premium combination filter from K&F that combines an ND filter and a circular polarizer. The build quality is excellent. The machining and anodizing of the buttons is very good. The selection doesn't move, but overall it's pretty easy to move. The knurling on the mounting ring ensures that it adjusts easily enough when adjusting the ND/CPL function to prevent it from twisting off. However, using this filter is a bit difficult and not as fast as using the standard filters separately. When you move one ring, it usually moves another ring. So you have to hold a ring still with one finger once you make a selection and then make the other selection with the other finger. This makes it very difficult to use on the go or while holding a fairly heavy lens and camera combination. It is best suited for landscapes/tripods rather than scenes where the light changes drastically. It can be set for a scene, but changing it requires some work. Sharpness doesn't seem to be affected too much when the filter is activated. However, there is quite a bit of red/purple color cast. In very bright lighting conditions there may be some purple/red flair. So make sure you are aware of this. This filter works like a combination filter, but has more limitations than using two separate filters. There are still situations where both are needed, it works well. I wish they would stick with the plastic case instead of the leather case they used for this filter. It's bulky and just doesn't stack as well as the plastic cases. The compromises make it a casual use filter for me, but overall in situations where it is used it has worked well.