Technical Data : “pH measurement : Measure range (-2.00 ~ 19.99)pH Resolution 0.1/0.01 pH Accuracy ±0.01 pH Input current ≤2×10-12 A Input impedance ≥1×1012 Ω Stability ±0.01 pH/3h Temp compensation range (0 ~ 100)℃ (automatic)” “ORP measurement : Measure Range -1999mV ~ 0 ~ 1999mV Resolution 1mV Accuracy ±0.1% FS, ±15mV” “Conductivity measurement : Measure range (0.00~19.99)μS/cm (20.0~199.9)μS/cm (200~1999)μS/cm (2.00~19.99)mS/cm      (20.0~199.9)mS/cm 0.01/0.1/1μS/cm 0.01/0.1 mS/cm Resolution ±1.0%,±1.5%FS Accuracy (0 ~ 50)℃(automatic) Temp compensation range ±1.0% FS Electrode constant 0.1 / 1 / 10 cm-1” “Dissolved Oxygen measurement : Measure range (0 ~ 20) mg/L (PPM) (0 ~ 200)% Resolution 0.1/0.01 mg/L (PPM) 1/0.1% Accuracy 0.10 mg/L, 0.40 mg/L Response Time <30 s (25 C, 90% response) Residual Current <0.1 mg/L Temp Compensation (0 ~ 45) ℃(automatic) Salinity Compensation (0 ~ 45) ppt (automatic) Pressure Compensation (66 ~ 200) kPa (manual) Automatically Calibration water saturated air; air saturated water Electrode Type polarographic” “Data storage 400 groups of data Data content test number,test value,test unit. Power AA batteryX2 Size&Weight Host:(65×120×31)mm/180g suitcase(360×270×76)mm/1.6Kg Quality&Certificate ISO9001:2000, CE&CMC”