This standard is to define the dimensions and connections for gas volume meters of membranes deformable used to measure volumes of fuel gases from the second or third families according to UNE-EN 437. Gas meters covered by the UNE-EN 1359 are considered within the scope of this standard. This standard does not include the operating conditions or requirements on the metrological behaviour, the design, materials used in construction, the mechanical behaviour and the marking of this type of meters because they are already specified in the standard UNE-EN 1359.