I have a few black mist type diffusers, including the more expensive K&F Nano-X, and even more expensive Tiffen. I bought this Nano-K series version half expecting to return it but thought it worth testing out given the much lower cost. Construction-wise it is as solid and well made as the Nano-X using the same finely machined “aircraft grade” aluminum. Screw thread is precise and smooth. K&F give very little useful information about the the actual differences between their filter series, except that the Nano-K is meant to be “basic level” compared to the supposedly more professional Nano-X and Nano-X Pro series. If you read the manufacturer’s small print, they are all made from optical grade glass from Japan, have advanced multi-coating and resistant to moisture and mold. So what about the effects performance? Again, I was prepared for disappointment. All brands of this type of black diffusion filter have subtle differences, as is well covered by numerous YouTube videos. The Tiffen for example tends to give slightly less intense diffusion for a given rating (i.e., 1/4 vs. 1/8 etc.) than the Nano-X, but both are equally good a preserving the blacks and fine detail in the mids, which is why we like them. When compared to the Nano-X, I can see no visible difference whatsoever in the image produced by the Nano-K. This was tested on a Canon C100 Mk-2 with a variety of lenses and conditions. For this reason, my advice would be, given the choice between the Nano-X and Nano-K, without hesitation get the latter. A side note: the Nano-K series appears to have been originally marketed in Germany, evident from Google searches and the small print on the packaging, i.e., GmBH, as place of origin. My conspiracy theory is that these were initially targeted for a European demographic and price expectations. Anyway, the bottom line is that here in Canada/USA they are a phenomenal bargain and not to be missed while available.