This is an inexpensive Chinese-made filter that has a good standard of manufacture and a decent coating. I'm not going to waste your time telling you what a polarizing filter does - if you're here looking for one, you already know! What I will say is that if you don't already own one, it's a very useful addition to your kit, especially if you're shooting outdoors or shooting reflective surfaces. POSITIVES * Good optics * Coated * Inexpensive * Comes with case NEGATIVES * Adjustment is made difficult by the extremely thin ring * Rotation is a little stiffer than I like * Filter case is huge - too big for a gadget bag and doesn't close securely. The optics are better than many I've owned in this price range, so no complaints. This is an ultra-thin filter, which helps avoid the risk of vignetting. The downside is that this makes ring adjustment tricky, especially with the slightly stiff rotation. With the lead rotating, the filter can come loose unless it's screwed on very tightly, making re-triggering a pain. Also, the front thread is so short that you can only use the supplied lens cap rather than the better one that came with your lens. Vignetting is only really a risk with ultra-wide lenses, and with medium to long lenses I personally prefer a deeper filter ring to allow for easier adjustment and the use of my original lens cap. It comes with a free lens cloth and lanyard, but I'd rather the money was spent on a better case. I consider this a budget filter for wide angle lenses. It doesn't have the same quality or technical capabilities as my Lee polarizing filter, but that's in a whole different price and performance bracket. You usually get what you pay for in photography, and at this lower end of the spectrum, the price/performance ratio of the K&F Concept version is solid and offers good value for money. I give it a solid four stars. One person found this information helpful