The CLD Series chlorine dioxide sensor from Sensorex, Garden Grove, CA, is available in 0–2 ppm and 0–10 ppm measurement ranges for use in applications such as water treatment disinfection and chlorine dioxide generators. The sensor provides real-time, amperometric chlorine dioxide measurement, operates over a pH range from 4–11, has an operating temperature range of 0°C–45°C, and has a max. pressure of 14.7 psig. It provides a 4–20 mA output, and installs via the Sensorex FC72 flow cell with 0.25 in. FNPT threads. Alternatively, it can be installed as a direct drop-in replacement for other chlorine dioxide sensors.