American Weigh Scales GEMINI-20 Portable MilliGram Scale, 20 by 0.001 G Powered by 2 AAA batteries (trial batteries included), best with Polaroid AAA batteries Weighs up to 20 grams in 0.001 gram increments Includes carrying case with tweezers, tray and calibration weight The flip-down shield protects the delicate weighing surface Backed by a powerful 10 year warranty