Description 30X Optical Glass Lens 6 LED Full Metal Folding Linen Tester Loupe Magnifying Glass Thread Counter Magnifier Specifications: Material: metal, double-layer optical glass lens. Product multiplying rate: 30X standard Product net weight: 165 g Product packing weight: 195 g Product size: 60*52*51mm/2.36*2.05*2.01 Package size: 70*65*62mm/2.76*2.56*2.44 Packing: leather case, white box. 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 large enough angle 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 front of the eyes, this problem can be solved. Convex lens is the simplest magnifying glass, which is a simple optical instrument to help the eyes observe small objects or details. Usage method: Observation method 1: Let the magnifier close to the object to be observed, and keep the distance between the human eye and the object to be observed unchanged. Then move the hand-held magnifier back and forth between the object and the human eye until the image is large and clear. Observation method 2: magnifying glass as close as possible to the eyes. The magnifying glass does not move, moving objects until the image is large and clear. Purpose: 1. An achromatic lens without chromatic aberration can observe pictures and identify gemstones very clearly. It has a packing box and is easy to carry. 2. It can also be used for jewelry certification test, substrate surface quality, color correction and other checks. Notes: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you 2. Please allow slight measuring deviation due to manual measurement. 1 X Magnifier