Spark Plug Wire Set for Mercruiser Stern Drives Part # 18-8804-1 GM;V-8 305, 350 THUNDERBOLT IGNITION, Conventional Mag Force Spark Plug Wire Set, Premium Marine Wire Leads, Magnetic Suppression Kevlar Core, Durable stainless steel wound conductor for maximun life, horsepower and engine performance,Superior RFI suppression for the most sensitive electronic systems, Corrosion resistant stainless steel spark plug and distributor terminals for maximum conductivity,OEM style boots provide a sealed barrier against heat, dirt and moisture replaces: Mercury Marine 84-813720A3 replaces: Mercury Marine 84-813720A2 replaces: Mercury Marine 84-813720A4 replaces: Mercury Marine 84-816761A4