JM-B系列电子天平经济型天平交直流两用带水准仪计数功能自动校准液晶背光功能全量程去皮内置RS232接口（选配）单位转换（克拉，盎司，磅，克）100g/0.1g200g/0.1g300g/0.1g100g/0.01g200g/0.01g1000g/0.01g2000g/0.01g300g/0.01g100g/0.001g200g/0.001g300g/0.001g)