RS-100A Nutrient-Wand PPM/EC/CF Tester£¨3 in 1£© Range: PPM: 280--3080, EC: 0.4¡ª4.4, CF: 4--44, Resolution: 0.1 EC Accuracy : +/- 4% full scale TDS Factor: 700ppm = 1EC = 10CF, Operating Temperature Range: 5 - 45¡æ(41-113¨H) Temperature Compensation Automatic up to 78F (25c) Features: Auto turn on & off, Auto turn Check. Battery Life: DC 3 x 1.5V Display: LED x 16