These custom made thermal sleeves can easily be fitted to the end of your spark plug wires. They will prevent the hot exhaust manifold or header from burning the wires, and causing a misfire. This is a very common problem with race cars, due to the excessive vibration at high RPM. Good for direct heat exposure temps of over 1200 degrees F. Little things cause big problems on the track, and these work really well. Much better than having to buy a new set of plug wires, everytime you burn just one of them. Race tested by some of the best known teams in the industry, they are now avaialable for your street car as well. Can be purchased in sets of four, or eight. Each package includes two racing decals.