The Aeroflow Performance crankshaft keys are designed to locate the crank sprocket on the nose of the crankshaft.They are a perfect replacementfor a worn key. Having worn crankshaft keys can result in timing gear to dampener positioning being incorrect which can cause your timing tobe off and inconsistent. Thesewoodruff keys are manufacturedto OEM specifications for quality and dimensions to ensure a proper fit. Whether you had a key go missing or you just want the peace of mind of a new one in its place, these are the perfect solution when rebuilding an engine.