Max-Fire Ultra-Spark 50 performance spark plug wires are manufactured from highest quality materials to help deliver maximum voltage – ensuring the ultimate performance. These wires have an extremely high EMI or RFI suppression along with a very low resistance to help deliver the most spark possible. They feature a heavy duty 8.5 millimeter diameter silicone jacket to protect the Kevlar spiral wound core from heat, moisture and chemicals. They are engineered for high performance engines that need all of the voltage they can get for maximum power output. Made with wire leads that deliver a low 40 ohms of resistance per-foot for maximum EMI or RFI noise suppression. This makes them ideal for engines with aftermarket high performance upgrades that require maximum voltage.