The TRZ03 series is an excellent representation of a proven and mature technology that is widely used throughout the natural gas industry due to its good price-performance ratio. The first generation was approved by PTB in 1993. Since then the meters have always exceeded the requirements of the relevant international standards. The TRZ03 is used both in the pipeline networks of the transport companies (TSOs) and in the transfer stations of the distribution network operators (DSOs) when high measuring accuracy for custody transfer operation, short inlet distances, robust and low-maintenance devices are required. In addition to the classic mechanical roller counter and the electrical pulse outputs, the meter can optionally be equipped with an encoder for serial transmission of the meter reading.