Description:

Nickel ground electrode for better heat dissipation. Copper core for better thermal conductivity. Machine rolled threads to reduce cross-threading and seizing. The plug insulator is constructed of purified alumina powder for extreme stress with 5 ribs to prevent flashover. Model # 4221 Features: Denso # 4221 Denso Traditional Nickel Spark Plug Special Tip NOTE: Plug has threaded terminal stud and does not contain terminal nut. If terminal nut is needed, order part#067606-0051.