Cleans Spark Plug Threads: Spark plug thread repair kit removes dirt and carbon from worn or corroded spark plug holes to help restore proper seating and firing, improving ignition system performance in engines with frequent plug changes. Two Sizes in One: spark plug repair kit features dual ends with 14 mm and 18 mm thread chasers to fit the most common spark plug hole sizes in automotive, motorcycle, and small engine applications. Works with Common Tools: Spark plug rethread kit designed with a hexagonal body for use with standard 13/16-inch deep sockets or open-end wrenches, allowing for quick and easy access in tight engine bays. Rust-Resistant Construction: Built from steel with a black oxide finish to resist rust and corrosion, making this spark plug rethreading tool a durable addition to any automotive repair kit or shop toolbox. Helps Prevent Cross-Threading: Realigns damaged threads for smooth plug installation and removal, reducing the risk of cross-threading and costly cylinder head repairs during tune-ups or engine maintenance.