The GoPro's 9 / 10 /11 already take really good pictures ex works, but with the help of ND/PL filters the pictures get even better. That's why I chose the set from K & F. The set was delivered in a storage box. The filters are simply offset to the left, then rotated slightly to the right and thus fixed. So a quick change is always possible. I use the ND/PL filters for photos and videos, whether for drones, system cameras and action cams. Because the colors come across more effectively and better. When it comes to ND/PL filters, I mostly use the ND8PL and ND16PL. ND32PL when it is extremely bright, in winter when it snows, on days with clear skies and clear sunshine. The ND64PL softens the fast movements in waterfalls and clouds, which comes across as silky. Everything else is razor sharp. It's best to try it yourself and then compare the results. The quality of the materials, including the glass, is impeccable and the processing of the filters is good. The attachment is easy and quick, they hold reliably, fit perfectly and the recordings are more professional. The PL filter minimizes mirroring and reflections. In addition, the images become more colorful and richer in contrast. Explanation of the ND filter: I use them for long-term exposure and depending on the sunlight. This allows you to take softer shots. What is a neutral density filter/ND filter? A neutral density filter is a filter where the glass is completely darkened so that less light can enter the lens. So it is possible to choose longer shutter speeds and to achieve the corresponding effects, such as foggy water or soft, long-drawn-out clouds. This would not be possible without a filter, as the image would be extremely overexposed or even completely white. About the neutral density filters: There are different variations of gray filters with confusing, different names from different manufacturers. I don't want to go into the different manufacturers here, just the different designations. I had to read through it first, but basically, it's easy to understand. The designations for this set mean: ND8 = slow down the shutter speed by 3 f-stops to increase the exposure time ND16 = slow down the shutter speed by 4 f-stops to increase the exposure time ND32 = slow down the shutter speed by 5 f-stops to increase the exposure time ND64 = slow down the shutter speed by 5 f-stops to increase the exposure time Shutter speed by 6 f-stops to increase the exposure time This allows outdoor scenes to be created very effectively and effectively. With the use of the various filters you will see how beneficial they actually are. Every professional works with such filters ;-) The polarization level can be adjusted with these ND/PL filters. I am very satisfied with this filter set and can clearly recommend it. Thank you for taking the time to read my review. I hope that I was able to help a little with this, also with the photos.