Denso universal oxygen sensors arrive without a connector, enabling you to reuse the old parts connector. Thimble type sensors feature a ceramic element that projects into the exhaust system and becomes electrically conductive at high temperature. The sensor element then sends voltage signals back to the engine management system to regulate the air to fuel ratio, for optimum efficiency. Denso oxygen sensors feature an aluminum-oxide trap layer to protect the ceramic from silicone and lead poisoning, preventing damage to the platinum electrode. Double protection cover maintains proper unit temperature for quicker response times and protects the ceramic element from contamination. Stainless steel housing resists corrosion and contamination with a rugged, watertight body. Porous PTFE filter allows atmospheric oxygen the enter the sensor without permitting water or engine contaminants to seep into the casing.