Accurately sets flowing fuel pressure on any carbureted nitrous system; Includes lab quality, liquid filled, fuel pressure gauge; accurate to within half a percentage point; Includes calibrated flow jets for nitrous systems jetted from 100 to over 400 HP; Compatible with all carbureted style nitrous systems The ZEX? Fuel Flow Check Tool is used to properly set flowing fuel pressure for any nitrous oxide injection system. Setting the fuel pressure on the nitrous system?s fuel feed line is critical for engine power and safety. Since most carbureted engines use dead-head style fuel pressure regulators, they must have fuel flowing through them to accurately set the fuel pressure. Trying to set fuel pressure under static, non-flowing conditionswill be very inaccurate. The ZEX? Fuel Flow Check Tool includes calibration jets that simulate the nitrous system?s fuel flow at various hp levels.