Beileshi Glasses Magnifier 10x 15x 20x 25x LED Illumination Double Eyes Jewelry Magnifying Loupe Eyeglass Repair Tools for Miniature Engraving Mechanical processing, electronic repair, jewelry appraisal, timepieces repair and miniature engraving etc. Included 10x 15x 20x 25x Lens , too high magnification can not to reading books. Left/right double eye patches magnifier with LED, It can't use both of eyes lens (when you working ), because focal distance from lens to product is 0.2-2in (0.5-5cm). 4 different magnifications can be interchanged quickly. If this magnifier is used for long time, you may use two lens barrels alternately to eliminate visual fatigue and improve work efficiency. Bracket and headband is interchangeable to each other. It is advisable to choose lens barrels of appropriate magnification according to the size of the object to be observed. BEILESHI is a registered trademark and is the only authorized seller of BEILESHI branded products