... % 4.Fetures: minimum flow velocity 0.01m / s water meter, ultrasonic water meter Item Performance, ParametersMeasurement principleUltrasonic time difference principle, the patent ... featuresTroubleshootingWith fault self-diagnosis function, with fault indicatorPower SupplyA single 3.6V Li-ion battery can work 6 years(Voltage ... will drop to 30%, significantly extended battery life Ultrasonic Water Meter