The high precision 36XiW-CTD series multi-parameter probes measure the conductivity, temperature and depth (pressure) of water bodies. Temperature dependencies and nonlinearity are precisely compensated by means of a mathematical model in the microcontroller. The integrated Pt1000 achieves an accuracy of ±0.1 °C and the conductivity can be measured with ± 2.5% of the selected range (0.2 / 2 / 20 / 200 mS/cm). The probes are equipped with SDI-12 interface and extended lightning protection.