I ordered the kit thatcomes with the required adaptor integrated with a UV filter plus the lens hood with magnetic lens cap. The first photo shows the adaptor/filter and hood whitout lens cap.

You can use the filter without the lens cap. I found no discernable difference in image quality when shooting with the filter. The second photo shows the adaptor with integrated UV filter next to an OEM adaptor fitted with a 49 mm UV filter. They are about the same size. The difference is that the 49 mm filter fitted on the OEM adaptor has a standard thread so, should you wish, you can easily add a variety of filters or hoods.

If you desire, add the lens hood. It screws into the adaptor. I love the look of the hood and cap. It works well, allhtough it does seem to block the viewfinder a bit. The hood screws on to the adaptor/filter. As a result, you need to use the protruding set-screw to maintain the desired hood orientation. This creates two problem. First, you need to tighten the set-screw enough to keep the hood aligned. The set-screw has a flat metallic surface that contacts the threads of the adaptor/filter. The means a possibility of thread damage. Second, the long set-screw protruces about 100 mm from the surface of the hood. This presents the possibility of getting caught on clothing, backpack straps or other surfaces.

Lastly, the system uses an unorthodox threading system. To accomodate the set-screw, the camera adaptor/filter has a male thread. It seems to be 55 mm and according to the manufacturer can be used with an appropriate adaptor and their magnetic filters or hood.

The last photo shows a comparison between the kit and TCL-X100II Teleconversion Lens. The lens uses 67 mm accessories. The K&F kit measures 65 mm square. The K&F kit is significantly shorter.

In summary, I love the look and am very happy with performance. I use it for general and travel photography when I have limited space and don't want a to carry too many gadgets. However, I try to be very careful not to damage my expensive camera, Further, I leave the kit home when I want flexibility.

UPDATE - October 11, 2024
I liked ths system so much I decided to purchase the K&F Concept Magnetic Circular Polarizers Filter (Magnetic Polarizing Filter + Magnetic Basic Ring + Lens Cap) with 28 Multi-Layer Coatings CPL Filter for Camera Lens (Nano-X Series). The MCUV Protection Filter Kit description states "The front of the uv filter adopts a magnetic + thread design, which allow 52mm magnetic filter / lens cap or screw-in filter to be installed on it. It provide more option for your creativity." The photos associated with the listing on Amazon.com also show 52 mm attachments. Foolishly, I ignored the measurements I made and ordered the 52 mm version of the CPL filter. Bad decision, as suspected, it did not fit. I will contact K&F Concept to confirm the 55 mm version of the CPL filter is the correct one to order.