tender for supply of tds testing device - pen type for civil department , item name , tds testing device -pen type  tds measurement range: 0 to 2000 ppm (mg/l) or 0 to 10.00 g/l for higher ranges.  resolution: 1 ppm (0-1999 ppm) or 0.01 g/l (above 2000 ppm).  accuracy: ±2% full scale (f.s.)  tds conversion factor: selectable or fixed, typically 0.45 to 1.0; 0.5 as standard.  temperature compensation: automatic temperature compensation (atc) from 0 to 50 °c  temperature range: 0.0 to 50.0 °c / 32.0 to 122.0 °f  calibration: automatic or manual, typically 1-point calibration.  probe/electrode: graphite or stainless steel conductivity electrode.  display: large lcd displaying tds and temperature simultaneously.  power supply: 4x1.5 v button cells (e.g., lr44 or ag13).  battery life: approximately 100-200 hours of continuous use.