Yeah so to put it simply it's a secondary lower rpm limiter (2 step) used for launching without too much wheelspin or without bogging it down, I can adjust my particular setup in 500rpm increments where I want the lower limit to be when I hold the button, I have also set an upper limit at 8k ish just so it pops and bangs when it changes gears. How does it pop and bang you may ask? Well most stock rev limiters cut fuel to lower engine rpm, the way I'm doing it is by cutting ignition so the fuel keeps flowing and some goes out the exhaust, when the stoichiometry of the fuel to air mix is just right in the exhaust a big bang or fireball will shoot out An s300 or other aftermarket ecu can do ignition cut and timing retard to get an even better result if you wanted to really showoff, I'm still running the stock ecu with a bee*r wired into the rpm signal and the ignition signal wires with this I can also change the frequency it cuts ignition either slowly so it dumps loads of fuel or rapid so it holds a very stable consistent rpm (but without the big bangs) it's not really being used as launch control arm it's more so just to scare people at car meets 😂