Oxygen sensors, also known as lambda sensors or O2 sensors are among the most sensitive and critical components in your car's engine. In order to function properly, the sensors must adhere to OE standards within incredibly close tolerances. A malfunctioning or incorrectly calibrated oxygen sensor can hurt driveability and illuminate the malfunction indicator, resulting in costly and time-consuming repairs. DENSO First Time Fit oxygen sensors are designed to meet those tolerances and more. Features: Corrosion resistant stainless steel construction PTFE filter blocks efficiency robbing contaminents Refined zirconia element improves sensor response DENSO First Time Fit parts meet or exceed all manufacturer standards, mount properly with a minimum of installation issues, and provide years of reliable service.