Dyna Coil Kit - Harley-Davidson Carb Models Sing Plug/Sing FireThe Twin Fire coil incorporates two individual performance ignition coils into one easy to mount package. This solves the problem of trying to mount two ignition coils on Harleys when installing single fire ignition systems. The Twin Fire coil is only slightly larger than the stock Harley coil and uses the stock mounting bracket. The Twin Fire coil will fit under the tank on XL AND FLH models as well as in the stock location on the side of the motor