It is a variable and polarizing ND filter. The ND is 5 steps, there are double, 10 steps (ND1000, 1024 to be exact). The polarizing filter eliminates light reflections on surfaces, cars, water, glass, also enhances the colors of the sky, leaves, asphalt, etc... (for more information search the Internet ) I personally use it for video, so as not to lose aperture-closing depth of field (f9 forward, now I can go to f2.3 without burning the frames due to excess light). I haven't removed it from my 35mm in a while, I'm delighted. The filter is made of metal and glass, presented in a rigid plastic case for storage. You can see the protective and anti-glare layers of a greenish color and you can put the dingle on it which holds quite well without staining. The lever changes the density of the filter and the other ring moves the polarizing filter. You have to be careful with this because you can move both carelessly. In the pictures you see the filter attached to an adapter, (step-up 49mm to 67mm) this is because I have 67 and 49 filters, my advice is to buy large filters then "step-up" adapters ". On image quality. Well, excellent: there are no casts, no chromatic aberration, no loss of definition or the terrible X of the ND gradual filters appear. I have a very expensive polarizing filter and barely notice the difference on it. As a negative point although I have already said it,