Since I treated myself to the new iPhone 17 Pro and the camera there is now so good that I often leave my large SLR at home, I still didn't want to do without using filters. In particular, I often lack a polar filter (CPL) in smartphone photos to get reflections from water or glass and make the sky bluer. The K&F Concept system is brilliantly solved. Thanks to the strong magnets (front and back), the clip securely holds the device. But the coolest thing is: It's a standard 58mm thread. This means that I can not only use the included CPL filter, but also screw on my old ND filters from the camera bag. The fit is precisely tailored to the 17 Pro camera module. Nothing is obscured, the flash remains free. The included CPL filter delivers great results — especially when taking landscape photos, the colors look much richer and reflections disappear. The small bag that comes with it is convenient to transport, as everything is well padded. Conclusion: If you want to get more out of your iPhone camera, you need this part. It almost turns the mobile phone into a professional camera. Price-performance ratio (just under 40 euros) is right for the quality.