NTK is the world's largest supplier and manufacturer of OEM oxygen sensors. Oxygen sensors play a critical role as part of the vehicle's on - board diagnostic system in maintaining optimal engine performance, maximizing fuel efficiency and reducing harmful emissions. Providing constant closed loop feedback to the ECU, oxygen sensors help to control the air - fuel ratio while alerting OBDII systems of possible problems with fuel delivery or catalytic converter efficiency. A ceramics company at our core, NTK uses state - of - the art technology enabling control of the ceramic element used in our oxygen sensors from raw material to finished product. Trust The Sensor Specialist for full - line market support and OE application technology.