Pocket Salinity Pen pH Range 0 to 14pH Electric Conductivity Range 0 to 20mS TDS Range 0 to 10ppt (g/L) Waterproof Yes Automatic Temperature Compensation Yes Salinity Range 0 to 100 ppm 1 to 10 ppt 100 to 1000 ppm Operating Temp Range (F) 32 Degrees to 194 Degrees F Operating Temp Range (C) 0 Degrees to 90 Degrees C Display LCD Auto Power Off Auto Power Off with Disable Memory 25 Readings Calibration 1 Point 2 Point 3 Point Power Source (4) CR2032 Batteries