Autolite racing spark plugs are the preferred choice for many professionals. They contain an Yttrium-enhanced alloy, which enables up to 8 percent reduction in side wire temperatures for improved durability and less pre-ignition. These replacement 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.