Electronic Volume Corrector Electronic volume corrector with integrated GSM modem. Execution of gas volume conversion from rotary, turbine, or ultrasonic gas meters. it is searched on google by many names like EVC meter, electronic volume corrector, electronic volume corrector manufacturer, Volumetric Flow Meter, Evc gas meter and gas volume corrector, etc. https://www.kimpexflow.com/product/electronic-volume-corrector-macbat-5