Attentions : 1. The optical axis of the eyepiece has been measured and fixed by the instrument, and the user does not need to adjust it. 2. Do not put the magnifier in the environment with direct sunlight to avoid outbreak of fire. Please place Magnifier in dark storage when not in use. 3. Do not use the magnifier to view the sun so as to avoid irritating eyes. Specifications: Magnification: 2.5X Interpupillary Distance: 64mm / 63mm / 62mm / 60mm / other size If your interpupillary distance is not as above, please contact to customize for you Working Distance: 300-500 mm Field of View: 100-158 mm Depth of Field: 92-220 mm Net Weight: 416 g Package Included: 1x main glasses with binocular loupes 1x headband 2x cover for binocular loupes 1x cleaning cloth 1x user's manual book 1x box Features: 1. Eyepiece: multi-layer lens, multi-layer coating, the mirror image is especially clear, the field of vision is wider. 2. Lens: the lens is made of imported Poly Carbonate material, which can be used directly by those who do not need to be corrected. 3. Frame: using carbon fiber frame, light weight, with anti-skid function, to prevent the magnifier falling from the ears. 4. Nose pads: soft, comfortable, suitable for all kinds of nose beams, without adjustment. 5. Comfortable binocular magnifier with ultra light material, the weight of less than 45g(not including frame). 6. It can supply large field of views and deep depth of view. 7. It is used for reduces dentist's eye, neck and shoulder fatigue, which is caused by long time lower head work. Here are some experience for reference: clinical application and magnification: 1. General dentistry, dental health, planting: 2.5X. 2. Dental crown, bridge work: 3.5X - 4.0X. 3. Laboratory Work, Technician: 4.0X - 5.0X.