ACDelco D1977A GM Original Equipment Ignition Coil Interface Module Feature electronically welded lead connections to reduce heat stress failure or cold joints Laser trimmed to provide precise values and reduce deterioration and damage Increase voltage in order for the spark plugs to ignite the air/fuel mixture Include a copper slug heat sink to help dissipate heat and create a more stable environment Equipped with a large bus bar for added support and conductivity to address the installation and operating forces that stress terminal tabs Note: Please refer to the tips on the Amazon A+ detail page below for better use