DENSO Oxygen Sensor front oxygen (O2) sensor.  Also known as an air/fuel ratio sensor  were rated as TWO TIMES MORE RESISTANT to silicone and lead poisoning.

Double-Protection Cover: First developed by DENSO, the double-protection cover assures quick response time by maintaining proper unit temperature in the ceramic element and protects the ceramic against outside lead and silicone poisoning. Available on all DENSO heated sensors.

Stainless Steel Housing: Rugged, watertight stainless steel body resists corrosion and contamination.

Porous tetrafluoroethylene (PTFE) Filter: This highly durable, heat-resistant material helps maintain the oxygen sensor's optimum performance. Porous tetrafluoroethylene allows atmospheric oxygen to enter the sensor without permitting water or engine contaminants to seep into the casing.

Aluminum Oxide Trap Layer: A DENSO exclusive, this specially designed aluminum oxide coating keeps silicone and lead outside the ceramic element and prevents silicone poisoning or damage to the platinum electrode.

Note: Product appearance may differ from photo.

Available for all Subaru WRX model years 2008 through 2014. (Specify your model year.)