V-Factor Sparkies RED Spark Plug Covers 90 Degree Boots For Most Harley # 18905

V-FACTOR Sparkies Spark Plug Cover Pair with RED Lens Fits all Harley-Davidson spark plugs with 90° boots Designed to show your engine's spark through colored lenses at the base of the wire Sold as a set of 2Also available in BLUE                                         Easy to install.  Just remove the rubber  boot that goes over the wire.  Slide the rubber boot over the spark plug wire. Then the Sparkie has a threaded stud if you look down into it.  Just thread this into yor spark plug Wire.    For these Sparkies to snap onto your spark plug, your spark plug will need a terminal nut.  If you look at the end of your spark plug and you see threads, you need the terminal nut.  Most spark plugs come with a terminal nut.