Nitrous Express Master Flo-Check Pro Gauge Kits Nitrous Express Master Flo-Check Pro gauge kits were designed for dialing in that exact fuel pressure for a perfect nitrous tune-up. The gauges display the fuel pressure for any nitrous system and are accurate to with +/- .01 percent. Each kit comes complete with a 6 in. gauge, all jets, fittings, and plastic molded carrying case.
