Deception of the customer through false information. The monocular is offered as a “12x50 HD mobile phone telescope”. The description states: “Full 12x magnification, 50 mm lens diameter” and again under “Technical data” “Lens diameter: 50 millimeters”. As soon as I unpacked the monocular I had the impression that the lens diameter was smaller than indicated. When measuring, it turned out that the lens diameter was only 40 mm. Another customer also indicated this in a review. I think it's quite bold to encourage the customer to buy by providing false information. With my other binoculars the information is always correct. If it says "* x 20, 30, 42, 63" or something else, the measured lens diameters also correspond to these details. With this monocular, customers are led to believe that there is a higher light intensity and a higher twilight factor, which is not true. These two pieces of information are essential in determining whether binoculars are suitable for twilight (not night or darkness). The higher the values are, the cheaper it is. If the 12x50 information were correct, the monocular would have a light intensity of 17.3 and a twilight factor of 24.5. In fact, with a lens diameter of 40 mm, it only has a light intensity of 11 and a twilight factor of 21.9. In addition to this serious drawback, I also noticed other criticisms: a) Edge blur. The blurring of the edges is clearly visible. It's even worse for people who wear glasses. The monocular is only suitable for people who wear glasses to a very limited extent. The middle image is useful.b) Mobile phone adapter. It is a cheap plastic adapter that is only suitable for certain mobile phones. It doesn't fit my Huawei mobile phone.c) User manual. You don't necessarily need one, but the included instructions are a joke. It is a general instruction on how to use normal double binoculars. General conclusion: Incorrect information about the lens, blurred edges, unsuitable for glasses wearers, unsuitable mobile phone holder, unusable instructions for use. These flaws cause me to only give the monocular one star. The monocular goes back. A device with such defects is too expensive.