The Blackjack Pro Series Ceramic Boot Spark Plug Wires use a high silicone jacket over a low-resistance shielded resistor core. These high-performance wires are the best way to ensure you get full voltage to your spark plugs. All wires are custom cut to fit, so you get that custom look with your set. We include both male and female style terminals. 8mm Silicon Spark Plug Wire Carbon Suppression Core Ceramic Boots to prevent burning on exhaust 50 ohms resistance per foot Custom Fit Cut to Length Available with 180°, 135°, or 90° boot jackets