Gas Turbine Meters have developed greatly since their introduction to the U.S. in 1963. From the mechanically gear driven version, meters have developed into fully electronic designs and self-correcting models. Although these technological developments have greatly improved the application of the meter, the meters basic design and principles have remained very similar. As an inferential meter, the gas turbine meter competes with the rotary and diaphragm positive displacement meters. Like these meters, the turbine meter is versatile and accurate over a wide range of flowing conditions. Unlike these meters the turbine meter provides less pressure drop for equivalent flow rates. It also provides a digital pulse output for input with flow computers and local readout devices. Accuracy, the meters ability to measure as close to actual flow as possible, are typically in the ±1% range or better. Repeatability, the meters’ ability to give the same readout under similar flowing conditions, is listed as ±0.1%. The meters ability to hook up with local pressure and temperature correctors as well as offsite flow computers allows the full versatility of the meter to be utilized; to provide corrected flow output and higher accuracy’s across its flow range