I’ve upgraded from the Action Cam 4 to the 6 and needed some new filters ready for the summer riding season. It’s a bit too dull in the UK right now for my use case, so even an ND8 is often more than I need, but I know these will be perfect once the brighter months roll around. I’ve used K&F filters on my older action cam, so I already trusted the brand, and these are the same high quality as my older ones. The glass is clear with no imperfections that I can see, and the fit is spot on. They screw on properly, which matters a lot to me because I use them on a motorbike. I’ve tried cheaper filters in the past that clip on or feel a bit loose, and they’ve fallen off mid ride. These feel secure and properly made.They also come with a little case, which is a nice bonus for chucking in a bag without everything rattling around. The packaging mentions “Optical Glass with 28 Layer Nano Coating”. I can’t test that in a lab, but I can say I ride in dusty conditions and I’ve had wind and grit leave tiny scratches on lenses before, so anything that helps with durability is a big plus for me.At £39.99 at the time of writing for four lenses, I think that’s a fair price for a full set from a brand that actually fits properly and feels made for real use.