When I was offered the 'K&F Concept 6.7 inch Magnetic Lens Filter Adapter', with a matching CPL filter, I simply had to say yes as a dedicated amateur photographer. The set comes in one of those dreadful smelling zipped 'boxes' that would actually be very handy. But you have to ventilate them somewhere for weeks before you no longer have the feeling that you are poisoning yourself with them. But then it is safe storage for the adapter and filter, which you can always leave on. For the sake of completeness, it should be mentioned that a shrink-wrapped microfiber cloth is also included. The 'MagSafe filter holder' is easy to describe. It sticks magnetically to the back of the cell phone and has a rectangular cutout just above the lenses. There is a 67mm filter thread in the middle of it, so that a filter screwed onto it covers all 3 iPhone cameras. It may have to be said that a CPL filter is pretty much the only optical filter on a cell phone that is still useful. It removes reflections that can't be solved with post-processing. Even if you get the reflections retouched away, what's underneath is still 'lost. ' You simply have to work with a CPL filter on or on the water to find out what I mean. It is almost magical when you can suddenly see 2-3 meters at the bottom of a clear lake, where the eye can only see a reflecting surface. Such a 'Circular Polarizing Lens' (CPL) creates a nice effect of additional depth even against the blue sky at certain times of day. For all these reasons, at least I will hardly screw any other filter onto this holder or even use it on my mobile phone. There is one small downside and that is the size of the lens cutout. It only fits the exact dimensions of mobile phone lenses without a protective case. However, most protective cases have a 'protective edge' around the lenses, which is too large for the cutout in the holder. Only a few millimeters are missing and it wouldn't be a problem if the cutout was larger by these few millimeters. I'm seriously considering whether I should go for it with a file. As it is, I either have to remove the protective cover or the MagSafe holder doesn't sit flat. This works if you use the adapter alone, but not if you want to continue using a MagSafe holder for your mobile phone, for example. That would work well because the filter holder at the back is itself magnetic. But if he doesn't lie flat, the cell phone doesn't hold well. My conclusion: The 'K&F Concept 6.7 inch Magnetic Lens Filter Adapter' is an excellent, practical product despite the small weakness with the cutout. You can safely place a filter on the mobile phone with a flick of the wrist, as opposed to any clamp. The magnet is very strong and the slightly rubberized back makes the holder on the mobile phone non-slip. I like to give the 'K&F Concept 6.7 inch Magnetic Lens Filter Adapter' 5 stars and a 100% purchase recommendation.