Genuine OEM GM/AC Delco part. New, in box. Not a reman or refurb. NOS. No Core. The ACDelco 12634064 Oxygen Sensor is a heated sensor designed to measure the amount of oxygen in the exhaust gas of a vehicle. Manufactured by ACDelco, this sensor is a crucial component in the exhaust and emission systems of cars and trucks. Its high-quality construction and reliable performance make it a trusted choice for maintaining optimal engine function and reducing emissions.