Inst ent up/down button, according to the number of carats displayed below the inst ent adjustment, you do not need to set the exact number of carats.But remember, for diamonds ( 1.0 carats), please turn on 1 green light; For diamonds (0.5 carats), turn on 2 green lights. For small gems (such as cuts or cones), turn on 3-4 green lights. (Please pay special attention not to touch the keys on the inst ent during testing). Intuitive Design Quick and Safe - Our diamond tester features an LCD display and LED indicator easy to read your precise testing results. Designed for quick, precise, and safe diamond testing, this diamond selector tester ensures that there is no harm to diamonds during the testing process. providing accurate results every time. Popular among professionals, hobbyists, coin enthusiasts, and business owners alike. Excellent tools. Excellent Value. Great gift idea. This pocket scale has 200 max weight capacity and reads weights in increments of 0.01g. High precision sensors make sure the accuracy. 6 weigh modes available - g/ oz/ gn/ ct/ / ozt.Tare & Auto-off: You can use the tare function to zero the weight of container within 200g. Energy saving by 3 minutes auto-off function. Portable Diamond Tester Pen and 60X LED Lighted Loupe each . Both items are small and can fit into any purse or backpack. Diamond Tester Pen and 60X LED Lighted Loupe combo and 200g/0.01g Mini Jewelry Scal is a must have tool kit when you are going to a garage sale, market, swap meet, etc. Alternatively, its also a great tool to have when testing your own jewelry. Application Range:Industrial Purpose, Circuit Board And Printing , Industry, Medicine, Gardening, Coin, Diamond,Stamp, Jewelry, Appraisal, Education, Geography, Home And Office.fast and safe This diamond selector tester designed for quick, precise, and safe diamond testing. No harm to diamonds. If you have any questions about use, please contact us. We expla