Amethyst from Aldon Automotive is a fully mappable system for distributor based ignition systems. Ignition curves can be configured using a laptop with a USB connection via the included software package. A soft cut rev limit can also be set up to 10,000 Rpm.Match ignition advance to suit your engines characteristics for improved performance and drive-abilityWorks with any distributor system with points or Aldon Ignitor electronic ignitionRPM plus Vacuum, boost or throttle position sensor inputsChoose from or modify pre-loaded ignition maps or upload your own existing advance curveAldon Automotive Amethyst mappable ignition is a great way to improve your engine performance, drive-ability and economy. Ignition curves can be matched to engines far better than they can with traditional bob weight and vacuum advance distributor systems. The dwell angle is automatically calculated to provide the strongest spark with minimum coil loading. If preferred the dwell can also be changed manually. T