I have a number of products from K&F, and in each case they are excellent products. These filters have a metal ring surrounding the filter, and there is a rubber lining on the inside of the filter to make it attach and stay attached once applied. *NOTE - the new Ace Pro2 cameras come with a silicone ring applied to the lens cover, and the filters will not attach over this ring. The ring must be removed, even though the manufacturer says not to remove the ring. It is all related to the "fogging" issues these cameras have had, but I experienced no difficulty using the filters. The hardest part was getting the silicone ring back on.

More importantly, the filters are optical excellence. There is no softening of the image and with a range from ND8 to ND128, this is neutral density to the extreme. I can't imagine needing something ND128, but if I want motion blur, this is the filter for that. There is also a polarizer, which is self explanatory, and again very high quality. Polarizers are a necessity, I believe, any time you are working around water - and they make the skies look great.

This is a very comprehensive set of filters from an excellent company, and I am very pleased. I recommend them.