They feature a low resistance conductor wrapped in durable, silicone double-layer jacketing for heat protection, strength, and durability. 8.5mm Blue Silicone and Synthetic Jacketing resist heat, oil, and abrasion.500 ohm per foot resistance delivering greater spark energy, while improving power, idle, and fuel efficiency.Spiral Wound Core conductor for greater strength and durability that suppresses Electro Magnetic (EMI) and Radio Frequency Interference (RFI).Matching Blue Silicone sheath protects against high exhaust temperatures.Double Spring Locking Terminals for secure-vibration proof connections.FIT FOR:8.5mm Blue High Performance UNIVERSAL Spiral Core Spark Plug Wires With 135 Degree (A.K.A. 45 degree) Spark Plug Fit For BIG BLOCK , SMALL BLOCK or any application that can use a 135 degree / 45 degree spark plug bootColor: RedMaterial: high temperature resistant siliconePackage Contents:1Set Spark Plug Set(1Bundle Spark Plug Wires+1PCS lubricating oil+1PCS splitter+1pack Dual Crimp Terminals+2pack Spark plug sheath+1pack Double Spring Locking Terminals)Only the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.