The Ignitor II has many of the same great features that the Ignitor has, but its smarter. Ignitor II units sense the coil current level and use a powerful micro controller to adjust the dwell. Variable dwell helps to maintain peak energy throughout the en Product Features:PerTronix 92561 Ignitor II Adaptive Dwell Control Prestolite distributor IAT-4403 6 cyl Adaptive dwell maintains peak energy throughout the entire RPM range, reducing misfires while improving engine performance.