The Ductus COI is an universal transit time ultrasonic flow meter. With the advanced large scale integrated circuit technology, it is well suited to most industrial environments for continuous flow measurement of homogeneous liquid. Although the system was designed principally for clean liquid applications, the instrument is tolerant of liquids with small amounts of gas/air bubbles or suspended solids found in most industrial environ-ments. The flow meter use state-of-the-art digital electronics and very powerful ultrasonic transducers to give high accuracy for pipe sizes between 25 mm and 2000 mm (up to 5000 mm possible depending on pipe material and conditions).