Twin Power Ignition Coil For Harley Softail High-quality, molded-epoxy coils for 12-Volt H-D ignition systems increase peak spark voltage by 20 or more! In a late O.E.M.-style molded case, these ignition coils improve starting, stops, high-speed misfires, mileage and overall performance. Features 0.4 Ohm Replaces OEM 31600017