Principle:In order to see the details of a small object, it is necessary to move the object close to the eye, so as to increase the angle of view and form a larger image on the retina. But when the object is too close to the eye, it can not see clearly. In other words, to be aware of the truth, not only should the object have a good enough to the eye, but also should take the appropriate distance. Obviously, for the eyes, these two requirements are mutually restrictive. If a convex lens is placed in the front of the eyes, this problem can be solved. Convex lens is the simplest magnifying glass, which is a simple optical inst ent to help the eyes observe Small objects or details.<br><br>Magnification: 10X Colour:black Material:plastic Size:41 x 44 x 45mm Lens diameter: 20mm<br><br>Package Contents: 1 x Scale magnifier<br><br>Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.