The Sper 850048 Combination Water Meter can Measure Dissolved Oxygen, pH, Conductivity, TDS, Salinity or Temperature Using Different Probes. This kit includes includes one conductivity/salinity probe. Additional probes (optional) also allow it to operate as a highly accurate pH meter, conductivity meter, TDS meter, Salinity meter or DO meter as desired. Probes change are easily changed and include specially designed guards to prevent tip damage. This meter is the ideal tool for numerous professional water testing applications including: aquaculture, laboratories, swimming pools, spas and water treatment facilities. • Large, backlit LCD can display multiple parameters including: pH, Conductivity, TDS, Salinity, Dissolved Oxygen, Temperature (using different probes) • Displayed parameter is determined by probe type • Green backlight for dark environment • Fast measuring of Dissolved Oxygen value • Accurate, replaceable probes with safety caps • Auto ranging conductivity measurement • Auto temperature compensation (ATC) • 99 points memories w/recall function • Multiple points calibration: 3 points for pH, 1 point for DO, 4 points for conductivity • Manually altitude and salinity compensation function for DO measurement • Available replacement probes • Temperature unit ?/? is switchable • 1 hour auto power off