Extech-Ex Stik-EC400-Conductivity-Total-Dissolved-Solids-TDS-EXTECH-EC400-P-The-Exstik-is-ideal-for-the-all-important-job-of-measuring-quantities-of-liquids-The-Exstik-is-highly-accurate-&-the-user-friendly-electrode-is-easy-to-change-The-device-also-possesses-a-bar-graph-display-&-a-storage-function-for-measurement-values-P-Extech-EC400-Conductivity-Total-Dissolved-Solids-TDS-Salinity-Temperature-Meter