As an amateur astronomer and professor of astronomy, I am used to evaluating binoculars and telescopes. This little monocular does the job perfectly. The one we bought gives a sharp picture, which means the optics (lenses) are of pretty good quality. The focal length range and the angle of view correspond to those specified. There are other higher magnification monoculars such as 10x, but they necessarily have a smaller field of view and give a "shakier" image when hand-held. This is small enough to easily fit in a coat pocket, which is what we wanted. I hope others have as good an experience with it as we have.