The McCormick 3678917M91 is a genuine OEM glow plug designed to provide efficient and reliable cold starting for compatible McCormick agricultural machinery. This essential engine component heats the combustion chamber, facilitating ignition in diesel engines, especially in colder conditions. Manufactured to McCormick's stringent quality standards, the 3678917M91 glow plug ensures optimal engine performance and longevity. It is a direct replacement part, guaranteeing proper fitment and function.