49mm Clear Natural Night Filter 28 Multi-Layer Coatings Light Pollution Reduction Filter for Night City Sky Star Shots, No Color Cast - Nano-X Series

Here's a quick look back at the image with the filter and without post-processing (except for the stacking for the circumpolar).
Without the filter, the pine tree is completely yellow and the sky is very pale orange or blue because I live in an urban area.

I was very sceptical at first, but taking these images shows that it helps make city took better at night. Well worth the money.

Passionate amateur photographer, not a professional. Review given without having used the filter in real-world conditions. I reserve the right to modify my review.
Ordered and received 2 days later, so excellent.
The plastic case is designed for a single filter but manufactured for 11 different diameters, limiting production costs. Too big, made of plastic, and the closure is unreliable. It seems fragile and brittle over time and with repeated handling, so not ideal. The filter screws on easily, even with my large fingers. Good construction, decent threading. So, very good.
In my case, permanently mounted on K&F adapter rings from 62 to 77 mm. The 77 mm K&F filter, with its adapter rings, fits perfectly into another 72 mm Gobe metal housing. The whole assembly is held perfectly using just the Gobe lens foam. No other adjustments were needed. This filter will fit my 62, 72, and 77mm Olympus lenses in one easy step. The price is reasonable; other brands offer it for more than twice the price, so given my beginner level, I'll practice with this filter and see how it goes, or not, and perhaps buy a higher-performance model if needed.

Another advantage of the Gobe box, besides being a metal candy tin, is its much smaller diameter compared to the K&F plastic one.

It's missing the cleaning cloth, which is included with competitors, like Gobe, for products in the same price range. Oh dear.
All that remains is the testing and use in real-world conditions. And there, I hope the magic will happen... After storing it untouched, I take the filter out, and to my dismay, it's so dirty, like a car windshield, even though it hasn't been out of the filter case with the other filters I use more often. Huge disappointment. It looks like grease stains that can't be removed, even with lens solutions and other filters. So, straight to the bin.

I haven't tried that out right now and am still trying it, but I've compared this shade to a (much more expensive) Kase 150mm filter which makes me believe it'll be fine. It's really well packaged and has a brown leather pouch to stash the filter, which actually fits pretty neatly in my Lowepro filter pouch - I think I'll keep it in the pouch as well, not just to protect it, but I will can easily be seen in the dark! This glass filter fits my Nisi and Lee holder systems perfectly, giving it five stars for the build quality and the fact that it looks like it is doing what I need it to be. I will adjust this review as I discover something different after taking the first batch of photos with it.

Addendum:

After my initial feedback, the seller proved to be very customer-oriented. Despite the issues with the product, my concerns were taken seriously, and I received a refund. The service was fast, friendly, and professional – that definitely deserves recognition! Thank you for the fair solution.

Original review:
This filter is a huge disappointment. After unpacking it for a long time and using it very little, it's already clear that the coating is dissolving despite normal storage in its own case. The quality leaves a lot to be desired – definitely not recommended!

Safe transport packaging. The lens shows no abnormalities in a rough overview. Shading or gradient are not visible. I think it's perfectly adequate for an 18-55mm lens. The filter will show its true colors the first time it is used. Therefore full marks first.

Good workmanship, good price-performance ratio.

I didn't buy this filter, I bought a 77mm size and I'm happy with the price.

I took a text shot with and without filters and I can assure you that the difference will be noticed a lot, especially in cities or in places full of light pollution. I can't compare myself to Nisi filters or other brands that are a little more expensive because I've never had the chance to try them, but I can be overall happy with this purchase.

The Natural Night Filter has arrived from delivery by post on time (4th of May) with the good price. I have tried it out at the night time, and it was brilliant. I am pleased that I have got it. In the future, hopefully soon I will try to take some photo of Milky Way if the sky is cleared.