Mir is the specification of this antenna completely unclear. Here at Amazon it is sold as "omni-directional" in the attached data sheet is but "directional" and "Yagi". There is virtually no documentation on this part, so no guide to installation / alignment; so you have to play around for a while, until you come to the best possible alignment.
The build quality is very high in my opinion, and it is diverse installation material for. Given the lack of information, unfortunately only three stars.