I purchased the 49mm version for €9.99, primarily to protect the front of the lens. I wonder if this type of filter also serves a secondary purpose, reducing UV. I mounted it on a Canon EOS M200 with an EF-M 15-45mm lens, the basic kit.
It screws on easily, has no play, and doesn't unscrew on my lens. It allows the use of the camera's original cap, and perhaps the attachment is even more convenient. It doesn't interfere with the tulip lens hood, whether used for photography or turned upside down for "storage."
I didn't notice any differences in the images. In one case of backlighting, it seemed to me that a direct beam of light hit it produced a larger halo. In any case, I'm attaching two images; the first is with the filter (1/160 f/4), the second without (1/160 f/4). Keep in mind that in the second shot, I wasn't able to get a direct ray of sunlight like in the previous one, and above all, I'm a poor photographer too. Bottom line: it doesn't seem to bother me and does its job. It definitely protects the lens from fingerprints, dust, and accidental scratches. I don't recommend trying to hammer it, but don't complain to me.