KL-139 TDS Tester Technical Specification: 1.Measuring range:0-1999 PPm(mg/L) 2.Resolution: 1 PPm(mg/L 3.Accuracy: ?%F.S 4.Operating Temperature: 0℃- 50℃ 5.Power Supply: 2?V（CR2032 Battery） 6.Environment: Humidity: ≤95% 7.Display:4-digital LCD 8.Weight:46g 9.Dimension:150mm?7mm?0mm Pocket sized and feather-weight for portable use in a large number of applications including Production and drinking of pure water,Cleanness of swimming pool water,Food processing,Hospitals and medical products,Aquatic cultivation,Boiler water,Households and offices,Aquarium water,Teaching of physics and chemistry,Electroplating water,Cooling towers,Laboratories,Ionized water and water quality testing etc.