Commercially available Daniel and Instromet 12-inch multipath ultrasonic flow meters have been tested at the Gas Research Institute (GRI) Metering Research Facility (MRF) in baseline and disturbed flow installations. This report presents test assess baseline accuracy and repeatability over a range of flowrates and pressures, and meter performance for two installation configurations. Comparisons are also made between the speed of sound as measured by the test meters and values calculated based on gas composition. These data demonstrate that the test meters are capable of accuracies well within a 1 percent tolerance and have repeatability of better than 0.25 percent when the flowrate is above about 5 percent of capacity.