The OTT C31 micrometer is a general instrument for measuring water flow velocity in rivers and open water. With thousands of devices installed in a wide variety of applications, the OTT C31 has proven its quality, accuracy and reliability. This micromole is suitable for use as accessories, as a micrometer mounted on a trap or as a micrometer hanging from a wire, to measure a range from 0.025 to 10 m/s, suitable for measurements in small and large rivers. It is also used in recycled cable systems, or for use in electronic devices.