... 3.Prestore famous brand reagent working curve COD220 portable COD analyzer with working curveFeatures1,LCD display, small size, light weight, ... measurement with less preheating time in the field or lab.2,Stored working curves of major brand reagents for ... Exel.4, Ease-to-use: display operation prompts, automatic zero adjustment,automatic readout concentration and absorbtion reading with sample No.after ...