Interesting, but 5

For those looking for a "gray" filter that reduces the light to make "long exposure". And here variably!
But beware, this is not really a simple neutral filter, but the juxtaposition of two polarizing filters.
He concludes that we turn to polarize the already polarized light of the first, to near darkness.
One thus finds there the disadvantage polarizing, which sometimes do not cover the entire image, leaving bright areas, especially in wide angle ... It is not always crippling, but not for purists

The whole is, however, extremely thin and well finished. Particular, there are gradations that can ensure how many steps (EV indexes, corresponding to a speed or diaphragm), it brings down the light (indicating to know to calculate bulb exposures, off limits cell ...).

And for the price, it usefully serve to start for those who want to try the long exposures, to make trials before stopping on a neutral density filter of fixed their convenience (choosing quality, paramount. ..). And we can also do extreme polarization tests.

In short, interesting product for exploring some areas.