K&F makes fixed filters and this UV filter is no different. My 24-70 has been naked for a while and I decided it was time to get it a protective UV filter as I've added it back to my rotation of travel lenses so I ordered a matching 77mm Filter. The K&F filter surprised me when I first unpacked it. First, the case is fantastic. It's a smoky transparent hardshell plastic case secured with 4 tabs and a quick twist to lock and unlock. It's a large filter housing as the same housing fits 82mm filters but can also fit smaller filters down to 43mm. And the filters don't slip around. But how? Inside the case are two tapered sections of silicone, a small one with 2 ribs and a large one with 10. The large one has numbers next to each rib indicating the size it fits (43, 46, 49, 52, 55 , 58, 62, 67, 72, 77, 82). The small one with 2 ribs is meant to hold the opposite end of the filter and stabilize it. As long as your filter is one of the sizes listed, it should fit this housing and be held securely in place by the silicone ribs. Now it holds my single layer filters with no problem, but it doesn't fit my variable ND filters or filters with rotating handles/extensions that protrude. The filter itself is very well made. The aluminum housing has built in two sections with thick knurling, making the filter easy to grab during installation and removal. The filter itself does not noticeably affect my image quality on my 24-70 compared to no filter when viewing an image up to 2x in Lightroom, nor do I notice any significant color cast. For me, the K&F UV filter is well designed and easy to use.