Twin cam 88 ignition coils require a specialized spark plug wire end, so not just any spark plug wire will do. Not only will they fit right, they will improve spark transfer and resist heat better than OEM wires. These 8mm wire sets feature a silicone jacket and have a suppresion style Spiro Pro core. The spark plug boot has a water tight seal with an easy to remove from the spark plug grip. Fits Softails 2000-later and Dyna models 1999-later.