When the original DiST? (Dissolved Solids Tester) was first introduced, conductivity and total dissolved solids measurements became easy and affordable. The DiST??s ease of use, in combination with its affordability, made it the standard in EC and TDS measurement. Hanna continues the standard in EC and TDS testing with the DiST?5. Waterproof Exposed temperature probe for fast response Low range EC/TDS 0 to 3999 uS/cm 0 to 2000 ppm (mg/L)