Portable Open Channel Ultrasonic gas flow meter is a ideal for liquids such as chemical,visous liquids, and sea water. The non-intrusive, clamp-on ultrasonic flow meter fits pipes between 1/2″ to 48″ internal diameter. Accuracy: +/-1.0% of FS Wide range: DN15mm-DN6000mm Medium: clean liquids,pure water Built-in rechargeable battery 3.6V Measurment unit: Meter, Feet,Cubic Meter.