Abstract: A fluid flow measurement assembly is shown and described. In a preferred embodiment, a flow conditioning section comprised of straightening vanes and a diffuser, as well as temperature probes, pressure transducers, and a metering assembly, are all provided in an integral housing. The assembly is provided with different sized flanges on an inlet orifice and an exit orifice, such that the assembly may be installed in a fluid line in only one direction, thereby preventing incorrect installation.The flow conditioning section is comprised of a diffuser and straightening vanes, and serves to ensure that fluid flowing through the measurement assembly is uniformly scrambled and then normalized, such that the metering assembly will be substantially insensitive to upstream flow disturbances and will provide accurate and repeatable fluid flow measurements.The metering assembly is comprised of two counter-rotating turbines, a pickoff device or pulse detector being provided for each turbine.