The Hose Monster flow meter implements pitot pressure technology to measure the velocity of flowing water at rates of up to 30 feet per second. Its ingenious T design makes it possible to easily diffuse high velocity water flows from a 2.5 in hydrant port. The accuracy of flow testing hydrants is greatly improved by using a calibrated pressure transducer and advanced Prolog data logger software to generate instantaneous velocity and flow data from the FM30 instrument.