1. Measurement Capabilities: The R-Tek RT - 5 IN 1 Water Testing Meter Is A Professional-Grade Handheld Device That Simultaneously Measures Five Vital Liquid Quality Parameters: PH From 0.00 To 14.00, Total Dissolved Solids (TDS) From 0 To 10000 Ppm, Electrical Conductivity (EC) From 0 To 10000 µS/Cm, Salinity From 0.01 To 25.00 Percent, And Temperature From 0 To 60 Degrees Celsius Or 32 To 140 Degrees Fahrenheit.