Autolite replacement racing spark plugs are the plugs of choice for many professional racers. These plugs contain an Yttrium-enhanced alloy, which enables up to 8 percent reduction in side wire temperatures for improved durability and less pre-ignition. Autolite racing spark plugs are available in colder heat ranges than most plug manufacturers to support modified engines. They feature a cut background electrode which improves ignitibility, and faster flame kernel growth. Autolite racing spark plugs have a nickel plated finish for long life and corrosion resistance.