ACDelco D585A Professional Ignition Coil High quality coated windings to improve durability and provide protection against internal shorts and dielectric breakdown Silicone steel plates surrounding the ignition coil correctly match the original part size and number exactly Laminations are coated to hinder corrosion and many feature molded plastic protection to help ensure that nothing is exposed Professional, premium aftermarket replacement Provides the performance and dependability you expect from ACDelco