The (4 pack) Autolite XP5683 Iridium XP Spark Plugs are high-quality direct replacement spark plugs designed for ignition secondary systems in vehicles. These spark plugs feature iridium material for enhanced durability and performance, making them a reliable choice for car and truck owners looking to improve their ignition systems. With interchange part numbers including NGK, Denso, S516, Champion, and Bosch 15-56, these Autolite spark plugs offer compatibility and quality assurance for a wide range of vehicles.