DiSt/H 2 O Pocket Conductivity Meters DiSt 3: Water conditioning (softener, demineralisation, aquariums, pollution control),DiSt 4: Agriculture, horticulture, hydroponics, cooling towers, boiling and steam heating plants, water purification,Pure H 2 O: Pure water, distilled and de-ionized water, steam cleaning, PCB washing, battery checking High accuracy, fast response, easy to read display and long battery life Single point calibration and auto temperature compensation for reliable readings Operating temperature range: 0 to 50°C (stock nos. 218-992 and 219-002 ); 10 to 40°C (stock no. 219-428 ) Battery life 150 hours continuous Batteries 4 x 1.4V Dimensions L x W x D (mm) 150 x 30 x 24 Weight (g) 85 Note Calibrate using the Conductivity Solutions (DiSt 3 stock no. 766-902 , DiSt 4 stock no. 766-918 and Pure H 2 O stock no. 766-895)