These NOS programmable nitrous controllers are an upgrade to virtually any nitrous system. They can be programmed to control both the amount of nitrous that is flowed into the engine (0-100 percent) and the time desired to "ramp up" from first hit to full flow. They can also be used to activate a retard box or a second stage of nitrous. These features enable racers to fine-tune the power curve of an engine to best utilize prevailing conditions. They are very easy to use, and each function is set through simply turning a series of dials to the desired position.