Can be used as a rev-limiter or RPM switch. As a rev-limiter, it guards against over-revving by allowing 100% power until reaching the pre-set RPM level, then interrupts ignition power for a fraction of a second to prevent over-rev. Includes by-pass delay to prevent activation of nitrous at starting line. This allows full power despite the RPM being higher than dialed in on the Pro-Conrol.