18 mm Oxygen SensorPrecision manufactured with a ceramic body of stabilized zirconium dioxide, surface coated with gas-permeable platinum electrodes and a porous ceramic to help prevent erosion due to contamination and particulates in the exhaust gases Slow reading oxygen sensors can cause a drop in fuel economy of 10-15%, excessive exhaust emissions and poor drivability Life expectancy of an average oxygen sensor in a properly tuned engine is typically 30,000-50,000 miles All sensors meet or exceed OE specifications Made in the U.S.A.