0.001g Precision Electronic Scales 100g/50g/20g Digital Weighing Gem Jewelry Diamond Scale Portable Lab Weight Milligram ScaleSupport USB plug-in power supplySpecifications: Capacity: 20g/50g/100g(for the same tpye have 3capacities,you need choose one you need) Readability: 0.001 gMinimum weight:0.01gErrorrange:+-0.005g Weight units: g/oz/ozt/dwt/ct/gn/tl/mg Tare range: Tare full capacity Powered:2 AAA batteries (not included) or USB plug-in(with USB cable) Auto-off: 180 seconds Platform size: 50mm Scale size (L x W x H): 110 x 63 x 15mm Net weight: 100 g Color: BlackKey features: High precision: Accuracy of 0.001 grams, use I-shaped sensor, fast reaction speed, accurate and stable with large blue backlitLCD display, easy to read, compact size, portable, lightweight Unique windproof cover design, prevents external environment disturbance affecting the weighing accuracy Count (PCS button) function with accurate count and tare weighing function ensures more precise result and the hold functionwill lock weight reading Mini digital scale can be used as a jewelry scale, lab scale, diamond scale and carat scale, ideal for jewelry, medicinalherbs, lab, powder or other small things weighingCalibration method:After turn on,press "M" button,it will show"100.000"g(50g and 20gcapacity is the same),press "M" button again,it will show "CAL" then flashing"100.000",put the 100g weights on the pan,it will show "PRSS "then "100.000" (sometimes show 99.999 or 99.998,it doesn't matter), Calibration complete.Package includes: 1 x Jewelry scales(don't include battery) 1 x Tray 1 x Plastic tweezers 1 x usb cable 1 x Calibration weights