ZEX Nitrous' Direct Port Nitrous Systems feature a unique dual stage jetting system that gives much finer cylinder-to-cylinder tuning options. One jet is used in the distribution block and one jet is used in the injector nozzle, delivering perfect nitrous and fuel distribution. These kits use patented fuel adjusting nitrous nozzles for a 50-200 HP adjustable increase. Safe enough for stock engines and ideal for fully built competition engines. Active Fuel Control monitors bottle pressure and when nitrous is engaged, it adds or subtracts enrichment fuel so the engine never runs too rich or too lean.