Delta meters are volumetric meters. They are used when very accurate measurement is required, when the gas ﬂow can be low or irregular. Due to the volumetric principle of the Delta meter, its metrology is not inﬂuenced by installation conditions. Consequently, it can be used to build very compact stations without installing a straight pipe inlet before the meter. Delta meters are approved for ﬁscal use. They are smart ready, meaning that they are all equipped for future communication needs.