All Moroso spark plug wires feature silicone plug boots that withstand high temperatures (up to 600°), and have a silicone jacket to reduce heat and chafing. Locking stainless steel terminals that stay connected under high vibration and are fully compatible with the Harley-Davidson® ION sensing coils used on virtually all late model bikes. Moroso High Performance Ignition wire combines state of the art engineering with the Finest “Made In the USA” workmanship and the very highest standards of quality control available.