Pertronix 71581 Ignitor III Electronic Ignition Module. Adaptive dwell maintains peak energy throughout the entire RPM range, reducing misfires while improving engine performance. Peak current level is reached just prior to spark for maximum energy without the heat build-up, increasing coil performance and module reliability. Adjusts spark timing at higher RPMs to compensate for the inherent electronic delay. Senses startup and develops more energy for quicker, easier starting. Senses crank orientation from either the distributor cam lobe or a PerTronix magnet sleeve. Thermal clad surface mount construction for high performance reliability. Memory safe function for user settings. LED user feedback for rev limit confirmation. Built-in reverse polarity and over current protection shuts down the system, preventing component damage.