Flow meter permits the convenience of testing net fire pump performance frequently without the cost of assembling a large group of personnel plus providing fire hoses and nozzles for each test.NAFFCO use flow meter of GLOBAL VISION as The new GVI digital gauge has a 4-20 ma output that can transmit flow data back to the controller, laptop or software. There is no bounce and is by far the easiest gauge to read. The GVI digital gauge is now FULLY FM APPROVED!!!! Their readings were so good, we are conducting 3rd party flow testing that will prove our accuracy is closer to 0.5%. IN ADDITION: the design is so revolutionary, we applied for a design patent which was accepted by the patent office. This makes GVI the ONLY fire pump test meter supplier with a Patented venturi. GVI’s new Design is FM Approved