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. While conventional switching oxygen sensors only switch rich or lean, wideband oxygen (or Air - Fuel Ratio) sensors produce a linear output signal that allows the ECU determine exactly how rich or lean an engine is running and make continuous and precise adjustments of the air - fuel mixture to stay closest to stoichiometric, providing the best possible combustion and fewest emissions. A ceramics company at our core, NTK uses state - of - the art technology enabling complete control of the ceramics used in our wideband oxygen sensors from raw material to finished product. Trust The Sensor Specialist for full - line market support and OE application technology.